
Class 
Book. 



TS Z.^0 






CpgyrightN"^ 1'^ dj I 



COFXRIGHT DEPOSm 



PATTERN MAKING 



A PRACTICAL TREATISE FOR THE PATTERN MAKER 
ON WOOD-WORKING AND WOOD TURNING, 
TOOLS AND EQUIPMENT, CONSTRUCTION 
OF SIMPLE AND COMPLICATED PAT- 
TERNS, MODERN MOLDING 
MACHINES AND MOLDING 
PRACTICE 



By JAMES RITCHEY 

FORMERLY INSTRUCTOR IN WOOD-WORKING, ARMOUR 
INSTITUTE OF TECHNOLOGY 

Revised by 
WALTER W. MONROE 

INSTRUCTOR IN PATTERN MAKING, WORCESTER 
POLYTECHNIC INSTITUTE 



ILLUSTRATED 



AMERICAN TECHNICAL SOCIETY 

CHICAGO 

1921 






COPYRIGHT. 1916, 1921, BY 

AMERICAN TECHNICAL SOCIETY 



COPYRIGHTED IN GREAT BRITAIN 
ALL RIGHTS RESERVED 



NOV -3 1921 






INTRODUCTION 

Pattern making is an art requiring the skill of a car- 
penter or wood turner combined with a rare mechanical 
knowledge and an ability to visualize the machines for which the 
patterns are to be made. This art has expanded wonderfully 
in the past few years just as other branches of our mechanical 
industries have developed, for the work of the pattern maker is 
the first step in most of the mechanical operations which result 
in a completed machine. Modern machinery is so complicated 
and has grown to such a size that the complexity of the patterns 
has increased in proportion. This has necessitated a greater 
skill on the part of the pattern maker in the design of the patterns 
and in the making of the cores, as well as a wider acquaintance 
with the various foundry methods which have their effect upon 
pattern construction. Furthermore, with the increase in the 
duplication of castings in modern manufacturing has come a 
wider use of metal master patterns, which have given rise to 
new responsibihties for the pattern maker, and have made him 
perforce a machinist as well as a carpenter. 

^ This article aims to cover fully the subject of pattern making, 
giving the tools and equipment necessary, the design details of 
simple and complicated patterns for typical cases, the use of 
green and dry sand cores, and finally the construction and design 
of a typical molding machine with details as to the manner in 
which the castings are designed to suit this machine. Both 
the original and the revising authors have had exceptional 
experience not only in practical work but in the teaching of the 
subject and it is the hope of the pubhshers that the book will 
be found of distinct practical value in its field. 



?l^^^pfC.^~v."- .-- 



>.^-v-^j 




HAL? UOL^, 46 mCilES BY 60 INCHZi V-V IS INCHES, V/EIGHiKG 4,000 POUNDS, MADS 

ON TABOR COMBINED MACHIK3 

C'- crtesy of Tahcr Manufacturing Camzjany, Philadelphia, Pennsi'ha-iia 



CONTENTS 



PAGE 

Practical requirements 1 

Characteristics , 1 

Working medium 2 

Ideal material 2 

Woods used 2 

Tool equipment 7 

Rip saw 7 

Crosscut saw 8 

Back saw 10 

Compass saw 11 

Iron plane 12 

Common types of planes 15 

Special planes 17 

Spokeshave 20 

Chisels 20 

Gouges 23 

Boring tools 24 

Bevels 27 

Rules 28 

Marking tools 29 

Calipers 31 

Forcing tools 33 

Abrading tools 36 

Turning equipment 40 

Sawing machines 46 

Planers 48 

Trimmers 49 

Allowances in construction 52 

General molding 52 

Coping out for solid patterns 54 

Molding difficult patterns 57 

Construction conditions 61 

Shrinkage . 62 

Draft 62 



CONTEXTS 

PAGE 

Construction of patterns 67 

Conditions of procedui-e 67 

Green-sand coring 67 

Topical construction 68 

Shaping pattern 70 

Finishing 74 

Gluing 81 

Clamping 83 

Built-up patterns 84 

Green-sand ring coring 84 

Making master pattern 85 

Dry-sand ring coring 89 

Building rim 92 

Forming hubs 94 

Construction for special size 95 

Arms 95 

Rim construction 97 

Use of loose hub 99 

Core prints 100 

Rim master pattern 100 

Standard core prints 105 

Flat-back patterns Ill 

Construction Ill 

Economical construction 116 

Example of faceplate : 116 

T-pipe connection 119 

Pipe elbow 122 

Return bend 123 

Screw chuck 124 

Deep flanges 124 

Large cylindrical work 126 

Quantity production 128 

Intricate coring 128 

Globe construction 128 

Two-part core 131 

Bonnet 133 

Small parts 135 

Steam-chest pattern . 136 

Core boxes 137 



CONTENTS 

PAGE 

Gear wheels , 139 

Accurate teeth required 139 

Patterned teeth 140 

Rim and arms 142 

Forming teeth 143 

Columns 150 

Patterns 150 

Cores 151 

Follow boards 151 

COMPLICATED PATTERN CONSTRUCTION 

Hand and machine-molded examples 153 

Conditions 153 

Guide vanes 155 

Vane core box 157 

Use of core box 161 

Bottom core 163 

Cover core 163 

Molding process 163 

Machine-molding practice 164 

Adaptation to production 164 

Increased uniformity ; 165 

Use of pattern plate 166 

Bearing-cap pattern 166 

Making pattern plate 168 

Molding metal pattern and plate 169 

Stripping draw-plate machine 171 

Flange-coupling pattern for hand molding 171 

Equipment for machine use 172 

Assembhng 173 

Typical deep-draw work. 176 

Stripping plate and draw board 178 

Parallel device 179 

Assembly 180 

Stripping-plate hand-rammed molding machine 182 

Hand-molding conditions 182 

Molding machine 185 

Stripping plate, . , 185 



CONTEXTS 

^AGE 

Stripping-plate hand-rammed molding m^achine (continued) 

Use of stool 189 

Use of match plate 190 

Ahgnment 191 

Use of roll back 191 

Green-sand cormg 197 

Characteristic usage 197 

Molding process 198 

Cope machine 199 

Drag machine 201 

Core-box construction 211 

Hollow roll cast on steel shaft 214 

Construction 214 

Operation 216 

Flask construction 219 

Inside core 221 




PATTERI^li I^JTJNTED IK ^TIBRATOR FRAME " 

CJppcr Left — ^Patterns in Frame; Upper Right — Drag Half of Mold; Lower Left — Hard Sand Match; 

Lower Right — Cope Half of Mold 

Courtesy of Tabor Manvfacturing Company, Philadelphia, Pennsylvania 



PATTERN MAKING 

PART I 



PRACTICAL REQUIREMENTS 

Characteristics. Pattern making dates back to the time when 
the first article was made from molten metal for the use of man. 
The pattern must precede the making of its metal counterpart, and 
is therefore the first subject to be treated in the working of metal. 

Woodworking, The pattern maker is essentially a worker in 
wood, though, where many castings are to be made from the same 
pattern, the final or working pattern is made of metal. These 
metal patterns are very serviceable, and leave the sand more easily 
and cleanly than those made of wood. Metal patterns are always 
necessary when the work is of a delicate or very light character. In 
all such cases, however, the first pattern from which the metal 
pattern is to be molded is made of wood, allowance being made for 
double shrinkage, and, when necessary, for double finish. The 
necessity for this will be clearly explained farther on. 

Knoivledge of Metals, The pattern maker should possess a prac- 
tical knowledge of the properties of metals. First of all, he must 
understand the shrinkage of metals, that is to say, how much smaller 
the cold casting will be than the molten mass as it flows into the mold; 
he should know what the strength of the metal is; he should be 
familiar with the relative rapidity of cooling, so that internal stresses 
in the body of the completed casting may be avoided as much as 
possible; he also should know enough about the practical work of the 
molder to decide upon the peculiarities of construction of the pattern 
for any given piece. 

Drafting and Designing. The pattern maker must be sufficiently 
skilled as a draftsman to lay out, without the assistance of the 
designer, the drawings of the piece to be made. This qualification 
is one of the most important. It is very true, however, that there 
are many good pattern makers who do not possess all of these 
qualifications. 



2 PATTERN MAKING 

The drawings furnished the pattern maker are usually on a 
small scale. In order to work to the best advantage, he must repro- 
duce a part or all of them at full size, as working drawings. To do 
this in such a way that the lines and curves of the finished pattern 
shall be graceful and artistic in appearance requires the same nicety 
and precision of workmanship that are demanded in the drafting 
room, and it is essential that the pattern maker have the same 
complete knowledge of the principles involved. To the extent, then, 
of being able, when necessary; to make a full-sized drawing of the 
article to be made, the pattern maker must be a draftsman. 

In large establishments, where all the work comes to the pattern 
shop in the form of carefully executed drawings, the pattern maker 
is the means of putting the ideas of others into tangible shape. In 
smaller places, where no draftsman is employed, the pattern maker 
will be called upon to work out the designs for which he is to make 
his patterns, and he thus becomes the real designer. 

Finally, the pattern maker is seldom required to make two 
patterns that are identically the same. His work, therefore, is 
varied, and he must be prepared to apply to the solution of new 
problems that arise such principles as he may already have learned. 

WORKING MEDIUM 

Ideal Material* As patterns are subjected to more or less 
rough usage, and are alternately wet and dry, it follows that the 
ideal material is one whose hardness is such that it will withstand 
the wear and tear of handling and at the same time be impervious 
to the effects of moisture. Such material is to be found in the 
metals, but, as the cost of working these into the proper shape is 
considerable, some kind of wood is usually substituted. 

Woods Used. White Pine. If, then, wood is to be used, 
another qualification is to be added — namely, it should be easily 
worlced. The best wood for the purpose is undoubtedly white pine. 
Care should be exercised in the inspection of the wood, to see that 
it is clear, straight-grained, and free from knots. The straightness of 
the grain can be determined by the appearance of the sawed face 
which should present an even roughness over the whole surface. 

The wood should be seasoned in the open air, but preferably 
sheltered by a roof, and should be piled so that the air has free 



PATTERN MAKING 3 

access to all parts of the plank. In the natural process of air-drying, 
the moisture slowly works out to the surface and evaporates until 
the wood is dry or seasoned. One of the characteristics of wood is 
that moisture is readily given off from its surface if the surrounding 
atpiosphere has a lower huniidity, and also readily absorbs moisture 
in case of being subjected to a higher humidity. In kiln-drying, the 
stock is robbed of its moisture to a point below that normally con- 
tained in outside atmosphere. This means that every time some 
of the surface stock is removed, exposing a new surface, the stock 
at this surface will either attempt to absorb moisture and swell, or 
moisture will dry out, shrinking the stock, and in either case warp- 
ing and disturbing the stock. This changing is always going on in 
pattern stock to some degree, but is less in stock that has dried or 
seasoned naturally to a point where there is about the same amount 
of moisture in the stock as there is in the atmosphere. It is best to 
\eep the pattern stock for some time before its use as nearly as 
possible under the same atmospheric conditions as it is in while the 
pattern is being built, This holds good w^hether the stock is air- 
or kiln-seasoned. 

It may be stated then, that, in the United States, white pine 
is the material commonly employed for pattern making. Lumber 
1 inch, Ij inches, and IJ inches thick will be found convenient in 
the construction of such patterns as are most commonly called for. 
It results in a great saving of time and labor, after the lumber has 
been carefully selected, to have it taken to the planing mill and 
dressed on two sides to the following thicknesses: 1-inch, dressed 
on two sides to | inch; IJ-inch, dressed on two sides to 1| inch; 
IJ-inch, dressed on two sides to If inch; and, if such can be found 
well-seasoned, a small quantity of 2-inch, dressed to If inches. 
In addition to these sizes there should be a moderate amount of 
1-inch resawed and dressed to f inch or to -f^ inch; and the same 
amount of l|-inch resawed and dressed to | inch. The last two 
thicknesses are used for gluing and building up the rims of pulleys, 
gear wheels, and other light work, where strength and durability 
are required. 

Hard Woods, Although pine is in general the ideal w^ood for 
pattern work, it is soft and weak, so that, if small and strong pat- 
terns are desired, a harder wood is usually employed. Mahogany 



PATTERN MAKING 



is much used for this purpose. Like pine, it b not liable to warp, 
and, when straight-grained, it is worked with comparative ease. 
There are many varieties of this beautiful wood, var>dng greatly in 
finnness of texture. The soft bay wood, often sold as genuine 
mahogany, should be avoided for patterns, being but little harder 
than pine. Cherry is also extensively used, but is not so easily 
worked to a smooth surface as mahogany, and is more liable than 
the latter to warp and to be affected by moisture. Black walnut, 
beech, and maple are used to some extent. Black walnut is stronger 
than cherr>% but, like beech and maple, is likely to warp. 

Warping of Wood. Observation shows that if one side of a 
board is kept damp and the other dried, the former will expand so 
that the plank, although originally straight, becomes curved, as in 
Fig. 1. Or if one side of a board 
is exposed to the air, while the 
other is more or less protected, 




Fig. 1. Board Warped from Unequal F»g 2 Warping of Pile of Boardi 

Dr>'nes3 

as in the stack of boards shown in Fig. 2, the exposed side of the 
upper board will give off its moisture more rapidly than the other 
side, and the board will warp or bend in the direction shown by the 
dotted lines. The second board will also draw up and to some 
extent follow the first, being in turn followed by the third, and so 
on until the entire stack is warped and bent. 

The same thing will be found trqe of a well-seasoned board if 
after being planed it is allowed to lie on its side on the work bench. 
The upper side will give off its moisture more freely than is possible 
for the under side, the latter being protected and having its 
moisture retained by the bench. The lower side of the board is thus 
caused to expand, and the Upper to contract, with the result that 
the board, although originally planed straight, becomes curved 
For this reason all lumber, even if well-seasoned, should be so placed 
in racks, or on end, that the air may have free access to both sides of 
the planks; and newly planed boards, however dry and well-seasoned, 
should never be stacked together, but so placed that both sides will 
be exposed alike. 



PATTERN MAKING 



This tendency to warp is explained to some extent by the 
porous nature of all woods, and their inclination to give off or to 
absorb moisture according to the condition of the surrounding 
atmosphere. As there is always more or less moisture in the air, and 
lumber of all kinds contains an amount of moisture which is ever 
changing according to the conditions of the surrounding atmos- 
phere, this causes corresponding expansion or contraction of the wood. 

Even under cover and in a dry place, wood has a tendency 
to warp on account of the greater shrinkage of the newer as com- 
pared with the older cells of the wood tissue or fiber in the side of 
the board nearest to the outside or sap wood of the tree. The inner 
side A of the board, Fig. 3, being closer to the heart wood, is older 
than the side B, and its cells are firmer and more compact than 
those of J5. As the board seasons, 
the newer and more open cells of 
the side B shrink faster and to a 




Fig. 3. 



Effect of Older Fibers in 
Warping 



Fig. 4. Reversing Layers in Build- 
ing Up 



greater extent than those of A, thus causing the board to draw or 
warp in the direction indicated by the dotted lines. 

Correction hy Reversing Grain. In gluing or building up stock 
for a pattern, this tendency may be corrected to some extent by 
reversing the grain of the pieces that are to be glued, and placing 
together two outsides, as B, or two insides, as A, Fig. 3. This is 
fully illustrated in Fig. 4. 

In gluing very thin pieces together for the webs or centers of 
pulleys and for other purposes, it is often necessary to reverse the 
grain of the pieces, or to place the grain of one piece at right angles 
to that of the other, for the purpose of gaining greater strength and 
stiffness. In such cases, if only two thin pieces are used, the result, 
to some extent, after they have been glued and dried, is as shown 
in Fig. 5, the shrinkage and strain of the end grain crosswise of the 
board at a, being sufficient to bend the opposing thin board length- 
wise of the grain at 6, while on the side cdy the curve is reversed for 
the same reason. Whenever it is necessary to cross the grain of thin 



PATTERN MAKING 




Warping of Two Thin Pieces 



pieces for a pattern, three or more pieces should be used, which will 
give satisfactory results if placed together, as shown in Fig. 6. 

When thin circular disks of large 
size are to be glued up for patterns 
of any kind, the strongest, stiffest, 
and most satisfactory results will be 
obtained if the pieces are fitted and 
glued tangentially to the hub or 
other center or opening in the disk, 
as shown in Fig. 7. The grain of the 
wood must run lengthwise, and par- 
allel to the longest side of each sec- 
tor; and, after the pieces have been 
fitted together, a thin groove is cut 
in the edge of each, in which thin tongues of wood are inserted and 
glued, as illustrated in Fig. 8. Two disks are glued up, and one 

is turned over so as to reverse 
the grain of the sectors of one 
disk on that of the other, as 
shown by the dotted lines. The 
disks are then glued together, 
making a very rigid con- 
struction, and one which, 
owing to the continual 
change in the direction 
of the grain, will not 
warp. 

Should a wide and 
thin piece of a single 
thickness be required for 
a pattern, the board from 
which it is to be made 
be ripped into 
strips of 2-, 3-, or 4-inch 
width— according to the width of the required board— and the strips 
glued together again with each alternate strip reversed, as shown in 
I ig. 9. In this way warping is largely corrected, each narrow strip 
being inclined to warp in an opposite direction to that of its neighbor. 




Flatness Obtained by Crossing Grain 
01 Three Thin Pieces 




Tangential Graining 



Fig. 8. Interlock- c|Toiilrl 
ing Tongues ^JlOUia 



1 



PATTERN MAKING 



Fig. 9. Reversed Grain of Strips for 
Wide Stock 



TOOL EQUIPMENT 

Distinction in Use. While many of the tools used by the 
pattern maker are identical with those used by the carpenter and 
cabinetmaker, yet the conditions which govern the construction of 
patterns for the molding of metals, together with the required accu- 
racy in dimensions, and the methods 
of construction used to guard against 
warping, distortion, and breaking, 
have very little in common with the 
workmanship and methods of the carpenter, the wood turner, or the 
cabinetmaker. 

Following is a descriptive list of the more essential tools used in 
pattern making, accompanied with instructions in their use. 



HAND CUTTING TOOLS 

Rip Saw. Hand saws are of two kinds — rip, and crosscut. 
The former, as the name indicates, is for cutting with the grain, or 
lengthwise of the board to be sawed. • In Fig. 10 is illustrated a rip 
saw having 5^ points to the inch, which will work rapidly and with 
ease in pine and other soft woods. If mahogany, cherry, or other 
hard wood is to be ripped, a 6-point saw should be used. 

Booh of Teeth. Rip saws should be filed with all the bevel on 
the back of the tooth, as shown at h in Fig. 10, the front or throat ol 
the tooth being at right angles to, 
or square with, the tooth edge of 
the blade, as at a. The position 
of the line cd, whether perpendicu- 
lar or slanting, is called the hook 
or pitch of the tooth. 

Filing and Setting, Rip saws 
should be filed square across; that 
is, the file should be held horizon- 
tal and at right angles to the side 
of the blade, always filing each alternate tooth from the opposite 
side of the saw; this, if done by beginning at the heel and working 
the file toward the point of the saw blade, gives a very slight bevel 
to the back edge of the tooth, causing it to cut cleaner and to require, 
less set than if filed otherwise. 



^rz^r--<r--ir-H^--g^zi:=q^=ja 



Fig. 10. Teeth of Rip Saw 



8 



PATTERN MAKING 




Rip saws require very little set for use in dry well-seasoned 
lumber, such as is always used in pattern making. The teeth should 
be set, or bent, only at the points, as shown at e and/ in Fig. 10 — 

in no case should the set 
exceed more than half the 
depth of the tooth. WTien 
the points only are set, the 
saw works more freely, and 
the blade of the saw is not 
sprung or bent in setting. 
In using a rip saw, the 
front or cutting edge of the 
saw blade should be held 
at an angle of about 45 de- 
grees to the board, as shown 
in Fig. 11. This brings the 
back of the tooth nearly at 
right angles to the fibers of 
the wood, and insures a 
shearing cut. For fine work 
and well-seasoned material, hand saws may be bought ground so 
thin on the back as to require no set. Such tools work very 
smoothly and easily, cutting away less wood and doing better work 
than saws that have been set. 

Crosscut Saw. The crosscut saw 
really severs or cuts the fibers of the 
wood twice, as shown at a in Fig. 12, 
the intervening projections being loos- 
ened and carried out as dust by the 
thrust of the saw, producing a nearly 
straight-bottomed kerf, as shown at h, 
A crosscut saw for ordinary work 
should have 5 or 6 points to the inch; 
but for fine work 10 or 12 points would be better, especially for dry 
woods, either soft or hard. A section of a 6-point crosscut saw is 
shown in Fig. 13, and one of a 13J-point in Fig. 14. 

Shape of Teeth. We find that while the rake or tooth bevel in 
rip saws is all on the back of the tooth, the rake in crosscut saws is 



Fig. 11. Position in Ripping 




D 



(b) 



Fig. 12. Kerf Made by Crosscut 

Saw 



PATTERN MAKING 



9 




Fig. 13. Crosscut Saw Teeth 



on the side of the tooth, as shown at a, Fig. 13. In ripping, the 
point of the tooth acts as a chisel, cutting off the fibers of the wood, 
each tooth chiseling off a shaving as it passes through the board; 
but in, crosscutting, the 
side of the tooth does 
the cutting, and there- 
fore must have its bevel 
on the side. 

In Fig. 13 the fleam 
— angle of the tooth with 
the plane of the saw blade — is about 45 degrees, and, as shown, 
there is no hook or pitch, the vertical angles being the same both 
front and back of the tooth. This form of tooth works well in wet 
or in very soft wood; but for wood that is well seasoned, and for all 
the harder woods, the pitch, or vertical 
angle or inclination, of the front of the 
tooth should be about 60 degrees to the 
tooth edge of the blade, as shown at 6, 
Fig. 15. The amount of pitch in the teeth 
of a saw may be varied for different pur- ^. ^ ^ . . ^. 

*' *■ Fig. 14. Crosscut Teeth for Fmc 

poses or for different woods, but should be '^^''J' 

such as to loosen and carry out the intervening wood. Otherwise this 

would have to be rasped or filed out by the continued action of the saw. 

Filing, The fleam or horizontal angle of the side of the cross- 
cut saw tooth IS very im- 
"J^ortant. When filing, 
the file should be held 
horizontally and at an 
angle of about 45 de- 
grees to the side of the 
saw, lengthwise of the 
blade, as illustrated in 
Fig. 15, and each alter- 
nate tooth must be filed from the opposite side of the blade, 
beginning at the heel and filing toward the point of the saw. 

The objection is often raised by saw filers, that, in filing from 
the handle end of the saw toward the point, a feather edge is made 
by the file and turned backward on the point of the tooth. The 





Fig. 15. Filing Crosscut Teeth 



10 



PATTERN MAKING 



first thrust of the saw through the board, however, will remove tliis 
featheredge entirely; whereas, if the filing is done from the point of 
the saw toward the handle, it is necessary to file the teeth bent 
toward the operator, which causes the saw to vibrate, or chatter, and 
this not only renders good even filing impossible, but breaks the 
teeth of the file. 

Setting, For hand and back saws, a saw set that acts on the 
principle of the hammer and anvil, such as the one illustrated in 

Fig. 16, is best, > The spring sets, 
so much in use, will not give so 
regular and even a set to the teeth 
as will one or more light blows 
with the hammer on the beveled 
face of the anvil. ' By this method 
the tooth is not bent or sprung 
beyond the position in which it is 
intended to remain, and the blade 
of the saw is not bent or affected 
by the stroke of the hammer on 
the point of the tooth. A saw set, 
of the kind shown in Fig. 16-, can be 
adjusted to set the points of the 
teeth to any depth desired; and, 
even if repeated light blows are 
given, the tooth cannot be bent be- 
yond the required distance. " The 
blow may be struck on a with a 
light mallet or it may be struck 
from below with the operator's foot 
on a treadle connected with e, leav- 
ing both hands free to hold and to guide the saw. 

In setting a saw, it is always better to use two or three light 
blows on a tooth than to try to do the work with one heavy blow; 
and this is especially the case if the saw is hard, as all good and well-, 
tempered saws should be. 

Back Saw. The back saw illustrated in Fig. 17 is used as a 
bench saw for light or fine work, and for fitting and dovetailing. 
Saws of this type are made from 8 to 14 inches in length, the 10- and 




Fig. 16. Saw Setter 



PATTERN MAKING 



11 




Fig. 17. Back Saw 



12-inch being convenient sizes for general work. As the metal back 
holds and stiffens the saw, a thin blade should always be selected. 
The methods of filing, jointing, and setting are the same as those 
described for the other hand saws. At least two back saws will be 
found necessary, one filed 
for crosscutting, and the 
other filed as a rip saw for 
cutting with the grain of 
the wood, as in the cutting 
of tenons and dovetails. 

Exercise. While for 
those who have had experience in carpentry the following exer- 
cise in the use of the back saw may not be necessary, it« is recom- 
mended to all beginners who wish to acquire skill in the use of 
this important tool. 

Take any block of wood from 12 inches to 16 inches long, about 2 inches 
wide, and about If inches in thickness. With try-square and a sharp-pointed 
pocketknife, lay it out, as illustrated in Fig. 18, on the upper, front, and back 
sides of the block. The knife cuts must be at least X2inch deep, and about 
I inch distant from each other. Next proceed to saw up the block into thin 
sections, sawing each time so that the saw kerf will be just outside of, but close 
to the knife line, as indicated at a. 

The saw cut through the block should be true to each of the three lines; 
and while the saw passes along one side of the line, its teeth should not scratch 
the opposite side of the knife cut, but should leave a smooth clean angle of the 
knife cut on the block, as shown at b in 
Fig. 18, while at the same time it should 
be so close to the line as to leave no wood 
to be smoothed off with plane ot chisel. 

A few hours' thorough and 
careful practice of this exercise will 
enable any one to use the saw suc- 
cessfully. 

Compass Saw. As the work 
of the compass saw. Fig. 19, is 
both with and across the grain of 

the wood, the best form of tooth is that shown in Fig. 20, having 
more pitch, and slightly less bevel, than the crosscut saw. A 
crosscut saw will rip better than a rip saw will crosscut; hence the 
shape of tooth should be between the two. Compass saws are 




Fig. 18. Example of Back Sax^^ing 



12 



PATTERN MAKING 



ground very thin on the back of the blade, but in order to turn easily 
they should be set the same as hand saws. 

And here we w^ish to impress on the beginner the necessity of 
keeping his saw — and, indeed, all other cutting tools — perfectly 




A^A^A^A^^A^^/v^/^A^A/vv^^^ 



Fig. 20. Compass Saw Teeth 



Fig. 19. Compass Saw 

sharp and in good working condition at all times. A sharp saw 
works faster, and always does smoother and better work with less 
set and with less expenditure of power, than a dull one. Even to 
saw well is an art, which cannot be gained through the use of dull, 

imperfectly set, and poorly kept 
tools. To file well will require from 
the beginner close attention, a study 
of. the subject, and careful prac- 
tice, all of which can be given by 
any one possessing ordinary mechan- 
ical ability. If the filing is done slowly at first, care being taken 
to hold the file at the same angle for all the teeth, a little faithful 
practice will always bring success. 

Iron Plane. The modern iron plane, illustrated in Fig. 21, can 
now be bought in a great variety of sizes and styles. These planes, 

with their true and unchang- 
ing faces, and their simple 
appliances for setting and 
adjusting the cutter, or 
plane iron, to the face of 
the plane and to the re- 
quired thickness of shav- 
ings, are greatly to be preferred to the old-style wooden planes. 
Construdicm, The general construction of the iron plane will 
be readily understood from Fig. 22, one side of the plane being 
removed to show the arrangement of the parts. The cutter, or plane 
irf>n a is made of the best cast stepl, and is of equal thickness through- 




Fig. 21. Iron Plane 



PATTERN MAKING 



13 




Fig. 22. Section of Plane 



out; in all new planes this part will be found ground and sharpened 
for immediate use. The cap iron /, Fig. 22, is fastened to tlie plane 
iron by an adjusting screw, as shown in Fig. 23. For whetting or 
grinding the cutting edge, 
it is not necessary to re- 
move the cap iron, but 
only to loosen the con- 
necting screw and to slide 
the cap back to the ex- 
treme end of the slot in 
the plane iron, tightening 
it there by a turn of the 
screw. The cap iron will 
then serve as a convenient 
handle or rest for the workman in whetting or grinding the blade. 

The iron lever c. Fig. 22, is held in place below its center by 
the screw g, which acts as a fulcrum, and the lever is readily 
clamped down upon the irons by the use of the cam piece d. 
When this cam is turned upward it ceases to bear upon the irons, 
and the lever c may then be removed from its place, and the irons 
released, without turning or changing the adjustment of the 
screw g, as the lever and irons are properly slotted for this purpose. 
Should the pressure required for the best working of the plane 
iron need changing, it can easily be obtained by tightening or 
loosening the screw g. 

When the plane iron is secured in its place, the use of the brass 
thumb screw h will draw or drive the plane iron, and thus the thick- 



Fig. 23. Plane Iron— Cap Iron Connection 



ness of the shaving to be taken from the work can be regulated with 
perfect accuracy. By the use of the lever e, located under the plane 
iron and working sidewise, the cutting edge can easily be brought 



14 PATTERN MAKING 

into position exactly parallel with the face of the plane, should any 
variation exist when the iron is clamped down. To ascertain this, 
hold the plane up, and look down over its face; the greater projec- 
tion, if there is any, of one or the other of the corners of the iron, 
can readily be seen. 

The cap iron/, which is not sharp, is not used for the purpose of 
strengthening or stiffening the cutting iron, as is often supposed, 
but as a chip break to prevent the cutting edge of the plane iron 
from chipping, tearing, and breaking the grain of the wood below 
the surface when the grain turns and twists, or when it is knotty 
and crooked. In such cases the tendency of the plane iron is to 
split and tear out the fibers of the wood in front of the cutting edge. 
To avoid this, the cap iron is screwed on, with its dull edge 
quite close to the cutting edge, so as to bend and break off 
the fibers or the shavings before the. split gets fairly started below 
the surface. 

The cutting edge of the plane iron is said to have lead in pro- 
portion to the distance it is placed in advance of the dull edge of the 
cap iron. The depth of the splits, or the roughness of the cross- 
grained surface, will be just equal to the lead of the cutting edge. 
For soft straight-grained wood the lead may be -^ inch or even more, 
but this must be reduced in proportion as the wood is curly, cross- 
grained, or knotty. 

Grinding. The grinding, or the whetting, must always be done 
on the bevel side only of the plane iron, the upper side being kept as 
flat and as smooth as possible to secure easy working. 

All plane irons should be ground slightly rounding to the extent 
of the thickness of a thin shaving. This rounding of the cutting 
edge should be the true arc of a circle throughout the entire length 
of the cutting edge, and not simply a rounding-off of the corners as 
is sometimes directed. Rounding the edge to the extent of the 
thickness of a shaving prevents the plane iron from grooving into, 
or plowing out a wide groove in the surface that is being worked, 
and also assists greatly in working the edges of the piece to right 
angles, or square with the face side. To do this, it is not necessary, 
should one corner of the edge be higher than the other, to tilt the 
plane on the high edge, but, while holding it flat and firm on the 
surface of the edge being planed, the plane should be pushed side- 



PATTERN MAKING 15 

wise toward the highest corner in order to reduce that corner. This 
is readily understood when we remember that the cutting edge of 
the iron is rounding. If the plane is held so that the middle of the 
plane iron does the cutting, the shaving planed is of the same thick- 
ness on both edges; but if the plane is pushed over to one side, either 
to the right or to the left, the shaving will be featheredged, or thick 
on one edge and thin on the other, thus reducing the higher corner 
of the edge of the piece. 

Proper Use. When the plane is to be used, the beginner should 
first carefully adjust it to the thickness of shaving required by mov- 
ing the adjusting screw in the proper direction, at the'same time 
holding it up and looking down over the face of the plane, when the 
projection of the plane iron can readily be seen. The cut should 
also be tested by trying it on the piece to be planed until the plane 
is ready for use. 

The operator's position should be one of perfect ease, standing 
well back of the piece to be planed, and pushing the plane to arm's 
length from, not alongside of, the operator, taking long and con- 
tinued shavings from the board. When starting the shaving at the 
end of the board, care should be taken to hold the forward end 
of the plane down firmly, or the act of pushing it forward will cause 
that end to tilt up and the plane iron to chatter on the surface as it 
begins to cut the shaving. This is due to the fact that nearly two- 
thirds of the plane overhangs the end of the board, requiring firm 
pressure on the forward end to balance it while the stroke is being 
started. 

To insure smooth work, care must be taken to plane with the 
grain of the wood, and not against the ends of the fibers as they lie 
in the surface of the board. Should the fibers tear out and the 
surface become rough, reverse the ends of the boards so as to cut the 
shaving in the opposite direction, and note the difference in the effect 
on the planed surface. 

Common Types of Planes. Jack Plane. Of iron planes, the 
most important is the No. 5 jack plane, 14 inches long, and having 
a cutter 2 inches in width, as illustrated in Fig. 24. When the 
pattern lumber has first been roughly planed in a planing mill, this 
No. 5 plane can be used almost exclusively for planing and pattern 
making. 



16 



.PATTERN MAKING 



Jointer Plane, In making or in truing up very large surfaces, 
or in making long glue joints, the No. 7 jointer plane, 22 inches long 
and having a cutter 2| inches wide, will be found necessary. This 
plane is shown in Fig. 21, and differs from the jack plane only in its 
length and in its extra width of face. 

Smooth Plane, For mahogany or other hard wood, the No. 4 
smooth plane, illustrated in Fig. 25, will be found very useful. This 




Fig. 24. Jack Plane 



25. Smooth Plane 



plane is made in several sizes. The No. 4, which is 9 inches long 
and has a 2-inch cutter, is the best size for general use, particularly 
for smooth surfaces. 

Block Plane. Next in importance to the three planes already 
mentioned, is the block plane, illustrated in Fig. 26. The No. 19, 
which is 7 inches long and has a cutter If inches wide, is the most 
desirable for the pattern maker's use. It has an adjustable throat, 
as well as the screw and lateral lever adjustments of the other planes. 




Fig. 26. Block Plane 



Fig. 27. Scrub Plane 



This plane has the advantage of being so constructed as to be held 
easily in one hand, a fact which makes it especially adaptable for 
for short work. Owing to the low angle at which the cutter is 
placed, it works more smoothly and easily on end wood and on 
miters than any other plane. 



PATTERN MAKING 



17 




Fig. 28. Circular Plane 



Scrub Plane, In cases where lumber must be dressed from the 
rough, without being first roughly dressed in a planing mill, the 
No. 40 scrub plane, illustrated in Fig. 27, will be almost indispen- 
sable. It is 9| inches long, and 
has a cutter IJ inches wide. The 
cutter is a single iron, and is 
ground and sharpened very- 
rounding on the cutting edge, as 
shown in Fig. 27, to allow of 
cutting a very thick shaving 
without grooving at the edges. 
This plane works rapidly and 
easily, preparing the rough-sawn surfaces of planks for the finishing 
planes. 

Circular Plane, For truing and smoothing circular arcs and 
curves of all kinds, either convex or concave, there is no tool that 
equals the circular plane, illustra- 
ted in Fig. 28. This plane has a 
flexible steel face which can easily 
be shaped to any required arc or 
curve by turning the knob on the 
front of the plane. 

Special Planes. Rabbet Plane, 
Among the special planes used by 
the pattern maker, the rabbet 
plane, llustrated in Fig. 29, is the 
most important. The face of this plane is always flat and at right 
angles to the sides. It is used in working out square angles and 
corners, or laps as they are called in carpentry, and also for working 
the lap joints, as shown in Fig. 30. 

The skew-iron rabbet plane, 
in which the cutting edge of the 
plane iron is set diagonally across 
the face of the plane, works much more smoothly and easily than 
one in which the iron is set at right angles to the side of the plane. 
The improved rabbet plane shown in Fig. 31 is fitted with depth 
gage, and also with a spur cutter, both of which are often of great 
convenience to the workman. 




Fig. 29. Rabbet Plane 



Fig. 30. Rabbeted Lap Joint 



18 



PATTERN MAKING 



Rabbet planes are made in sizes ranging from ^ inch to 1§ 
inches in width. The 1-inch and IJ-inch are convenient sizes for 
general work. 

Round and Hollow Planes, These planes are illustrated in 
Figs. 32 and 33. They are made of different curvatures, and a set 

of assorted sizes, especially 
the rounds, are almost in- 
dispensable to the pattern 
maker for finishing semi- 
circular core boxes, for 
making fillets, and for 
working out curves of 
every description, both 
concave and convex. 
Core-Box Plane, The core-box plane, shown in Fig. 34, while 
not indispensable, will be found to be a very rapid working and 
useful tool for making semicircular core boxes up to 2^ inches in 
diameter. By using the extension sides, one of which is shown in 
the illustration, and two pairs of which are always furnished, this 




Fig. 31. Improved Rabbet Plane 




Fig. 32. Round Plane 



Fig. 33. Hollow Plane 



tool will work accurately a concave semicircle up to 10 inches in 
diameter. 

The core-box plane is constructed upon the principle that if 
the sides of a right angle lie upon the extremities of the diameter of 
a circle, the vertex of the right angle will lie upon the circumference 
of the circle. This is illustrated in Fig. 35, from which it wiU be seen 
that if the block of wood has been worked to a perfect semicircle, 
and the edges of the blades of a try-square or right-angled triangle 



PATTERN MAKING 



19 



touch the semicircular curve at its extremities, the right angle or 
corner will touch the arc at some point, as h, e, or A, and the angles 
ahc, defj and ghi will all be right angles. 

To this kind of plane the objection is often made that it abrades 
and wears off the corners of the semicircle as it is being worked out. 

This, however, can be prac- 
/^^ /^ tically avoided if the fol- 
lowing instructions are put 
into effect: 

Carefully lay out the block 
from which the core box is to be 




Fig. 34. Core-Box Plane 



Fig. 35. Profile Cut by Core-Box Plane 



worked, from a center Hne on the face of the block, describing on each end of the 
block a semicircle of the required radius; connect the extremes of the two end arcs 
by straight Unes on the face of the block, as shown in Fig. 36. Two very thin 
strips of hard wood are tacked along these Unes, just outside of the wood to be 
cut away, as shown at a and at h in Fig. 37. These strips form rests for the sides 
of the plane while the heavier part of the work is being done. After working 




Fig. 36. Block Laid Out for Core-Box 



Fig. 37. Protection of Edges in Forming 



out the semicircle as far as the strips will allow, as shown by the dotted arc ach, 
the strips are removed, when the work can be finished without materially affect- 
ing the corners at a and 6. 

When making the finishing cuts with this plane, care must be 
taken to adjust the cutter centrally, i.e., so that it will cut equally 



20 



PATTERN MAKING 



to both right and left; otherwise the work will not be correct. If, 
however, the work has been done with care, the finishing may be 
completed with coarse, and lastly'with fine, sandpaper held on a 
cylindrical block of radius slightly less than that of the required 
core box. 

Router Plane. This tool, illustrated in Fig. 38, will be found 
very convenient for smoothing out sunken panels, for letting in 

rapping and lifting plates, 
and for all depressions 
below the general surface 
of the pattern. It will 
plane the bottoms of re- 
cesses to a uniform depth 
from the surface of the 

Fig. 38. Router Plane ^^^^k, and wiU WOrk luto 

angles and corners that otherwise could be reached only by the use 
of the paring chisel. 

Spokeshave. The spokeshave is used by the pattern maker 
for shaping and rounding out small curves, either convex or con- 
cave, which cannot be reached with the circular plane. It can 
be found in a great variety of styles, either in metal, as shown in 
Fig. 39, or in wood. The all-wood boxwood spokeshave illustrated 





Iron Spokeshave 



Fig, 40. Wooden Spokeshave 



in Fig. 40, without brass facing or screw adjustment, is to be 
preferred to all others for the pattern maker's use, especially for 
working pine or other soft wood. 

Ch isels. The chisel enters so largely into the work of the pattern 
maker in paring and shaping patterns that the quality of the tool 



\ 



PATTERN MAKING 



21 



should be of the best. While carpenters' chisels are made in several 
styles, they may be divided into two general classes: socket-handled 
chisels; and firmer or paring chisels. The former are illustrated 
in Fig. 41, and are used for framing, and for very heavy work of 
all kinds in which the use of a mallet is necessary. 

Common Paring Type. The common firmer or paring chisels, 
two styles of which are shown in Fig. 42, are the best all-around 



.^^ 



XECO 



^^^CIDD 



Fig. 41. Socket-Handled Chisels 

chisels for pattern work. Being lighter and thinner than the others, 
they are better adapted to the light work on which they are used; 
moreover, when used with care, they will answer every desired 
purpose, even for heavy work or with a mallet. The beveled-edge 
chisel shown at a. Fig. 42, is greatly to be preferred, it is lighter 
than the other kind illustrated, and, the square angle being removed, 



>^crOD 



Fig. 42. Paring ChiseLs 



the workman is enabled to reach into angles and under projections 
difficult to reach wdth a square-edged tool. A set varying in width 
from I inch to f inch by eighths, and from f inch to 1| inches by 
quarters, nine chisels in all, will be found useful. 

Examples of Use, The manner in which the chisel is used is 
so obvious and simple that any instruction in that direction would 
seem unnecessary. We shall only say in a general way that, in using 



22 



PATTERN MAKING 



a chisel on a flat surface or in a recess, it should always be held with 
the flat or back of the chisel against the work, and, whenever possible. 




Fig. 43. Method of Using Chisel 

it should not be pushed straight forward or straight through an 
opening, especially when paring across the grain of the wood, but 
should be moved laterally at the same time that it is pushed forward, 
as indicated by the dotted lines in Fig. 43. " ^^^^fm^^^^^ 
This insures a shearing cut, which, with care, 
even when the material is cross-grained, will 
produce a smooth and even surface. 

As an exercise for acquiring the free use 
of the paring chisel, there is nothing better for 
the beginner than the simple hal£-lap joint 
shown in Fig. 44. 





Fig. 44. Half-Lap Joint 



Fig. 45. Dovetail Joints 



The shoulders or the ends of the openings must be cut \sith 
back saw. The opening is then cut out and the shoulders 



PATTERN MAKING 23 

smoothed with a wide chisel, and a perfect fit obtained by con- 
tinued trials. 

The two dovetail joints, shown in Fig. 45, may be attempted 
after having succeeded with the half lap; and these exercises should 
be continued by the student until such control of the chisel is 
attained that this and similar work can be done with ease and 
certainty. For laying out work of this kind the blade of a pocket- 
knife or bench knife should always be used. This gives a clean 
sharp cut angle for the meeting sides of the joints, which cannot be 
obtained if a scratch awl is used. The awl tears and breaks the 
fibers of the wood, producing a rough ragged angle, which, on fitting, 
cannot produce a smooth and close piece of work. A pencil is 
equally objectionable because of the inilefinite dimensions given 
by its use. 

Gouges. The paring gouges used in pattern making are 
ground or beveled on the inside, as shown in Fig. 46. These gouges 



Fig. 46. Paring Gouge 



I'ig. 47. Common Firmer Gouge 

are made in regular, middle, and flat sweeps. They are indispensable 
for working out core boxes and other curves. 

In selecting a set of paring gouges, they should be not only of 
assorted sizes, but of different sweeps, so as to work out semicircles 
and curves of different radii. 

The common firmer gouge, illustrated in Fig. 47, is a useful 
tool for rough or heavy work, but in general its use can be dis- 
pensed with in pattern making. 

Front Bent Type, An assortment of four to nine carver's gouges, 
front bent, as shown in Fig. 48, will be found necessary for working 
out short deep curves, and in places where a straight gouge cannot 



24' 



PATTERN MAKING 



be used, as in the core boxes for a globe valve — shown in Pattern 
Making Part II, Figs. 233 and 234— and for similar work. 

The full set consists of nine tools, the curves of which are 
numbered from ^4 to ^;^. The two extremes, Nos. ^4 and 32, are 



32 



\y 



25- 

27 V 
28v, 



20v_X 
30 v,^ 

3lv V 



Fig. 48. Carver's Gouges 



shown in Fig. 48, and also the shapes of the curves of the seven 
intermediate, Nos. 25 to 81, inchisive. If desired, to save expense, 

each alternate tool might 
be omitted from the set, 
only the odd numbers 25, 
27, 29, and 81 being select- 
ed, and for ordinary work 
these will be found suffi- 
cient. 

Boring Tools. Brace. 
Among the necessary tools 
are the brace and an assortment of boring bits. The most desirable 
style of brace is the ratchet brace, illustrated in Fig. 49. The con- 




Fig. 49. Ratchet Brace 




Fig. 50. Auger Bits 

venience of the ratchet will, soon be apparent from the necessity, so 
often arising, for boring holes or driving screws in angles or close 
to projections where the full sweep of the brace cannot be taken. 
Braces are made in many sizes, with sweeps varying from 6 inches 
to 14 inches in diameter. 



PATTERN MAKING 25 

A brace with an 8-inch sweep is the most convenient in size 
for boring holes 1 inch or less in diameter in soft wood. For larger 



^ 




^3 



Fig. 51. Extension Bit 

holes, and especially in very hard woods, a 10-inch or 12-inch sweep 
is necessary. 

Bits. Wood-boring bits are made in many styles. The most 
important are the auger bits, two styles of which are shown in 

Fig. 52. Gimlet ana Wood Drill 

Fig. 50. They can be bought in sizes running by sixteenths of an 
inch from -^ inch to 1 inch. For holes larger than 1 inch, the No. 2 
extension bit, shown in Fig. 51, is the best. It has two cutters, 
and will bore a hole of any size from | inch to 3 inches in diameter. 

For screw holes, the s_ 

gimlet bit or the twist drill LL .. ^ -^ 

for wood, both of which 
are illustrated in Fig. 52, 
are used. They can be 

bought ia all sizes run- ^'^-^^ Brace Screwdnver and Countersink 

ning by thirty -seconds of an inch from ^2 inch up to | inch. 

The brace screwdriver, and also the brace countersink for 
screw heads, are important tools. They are shown in Fig. 53, and 
can be bought in large, medium, and small sizes. 




26 



PATTERN MAKING 



MEASURING TOOLS 

Squares. The best try-squares are now made. with blades 
graduated, and from 2 inches to 12 inches in length. Several sizes 



^ 



5 



4 3 



2 1 



FIT 



Fig 54. Try-Square with Fixed Blade 



of the _fixed-blade type, 
Fig. 54, are needed, as 
in many cases the blade 
must be short to admit 
of its application in pat- 
tern work. 

Adjustable Try-Square. 
The adjustable try- 
square, illustrated in Fig. 
55, is not expensive, and 
will be found to fill the 
requirements of several 
small squares. It is made 
in two sizes, with gradu- 
ated blades 4 inches and 
6 inches in length, re- 
spectively. The blade of 
this square can be firmly 
secured in its seat at any 
point. When the blade 
is carried entirely to the 
front of the handle, it is 
like an ordinary try- 
square; and the movmg 
of the blade makes the 
square equally perfect 
down to I inch length of 
blade, or even less. With 
one adjustable square of 
this kind, six inches in 
length, only one 8-inch 
or one 10-inch ordmary 
square will be necessary. 
A still more convenient, but slightly more expensive, form 
of adjustable try -square is shown in Fig. 56. It differs from that 




Adjustablc-Blade Try-Square 



TTTpTT 



TTTTTTT 



TTTJTTT 



lililililililililililililillilililililihlililililililild^ 



Mil 



'MMI' l j 



Fig 5G. Removable-Blade Try-Square 



PATTERN MAKING 



27 



shown in Fig. 55, in being self-contained, no screwdriver being 
necessary for moving the blade or securing it in position, and also 
because the blade can be removed entirely, and an extra blade, 
shown in Fig. 57, substi- 



^ 



Fig. 57. Try-Square with Bevel-Ended Blade 



tuted. The ends of this . . 

second blade give both ''V V^ 11 I -^ 

• the hexagon and octagon 
angles, which is a matter 
of great convenience to 
the pattern maker. Fig. X^v^ 
57 shows the hexagon 
end of the blade applied. 
to a hexagon nut. By 
reversing the blade the octagon end will be in position for use. 

Car'penter^s Square, To the above try-squares there should be 
added a carpenter's steel square, 24 inches by 18 inches, for use in 
laying out and squaring up large 
stock and large patterns. 

Bevels. The bevel illustrated 
in Fig. 58, with the clamping screw 
in the end of the handle, is the 
most accurate and the most easily 
adjusted style of this indispen- 
sable tool. The blades are made 
from 6 to 12 inches in length, and 
have a slot in at one end, which 
admits of that end being adjusted 
to meet the requirements of the 
work. 

Universal Type. The small 
bevel illustrated in Fig. 59, like the 
adjustable try-square, is not an 
expensive tool, and will be found 
generally useful, especially in working the draft on patterns, and in 
turning the parts of patterns on the wood lathe which cannot be 
reached with an ordinary bevel. The ofl'set in the blade increases 
its capacity and usefulness, so that any angle, however slight, may 
be obtained. 




Fig 58. Bevel 



28 



PATTERN MAKING 



One 3-inch universal, and one 8-inch or 10-inch ordinary bevel, 
will meet all the requirements of the pattern maker for the beveled 
edges and surfaces and the draft of pattern work. 

Rules. For all ordinary measurements, a 2-foot folding stand- 
ard rule, Fig. 60, will be sufficient, but this rule must not be used 




Univorsal Bevel 



for laying out or for working patterns, or any part of a pattern or 
core box, to the required dimensions. 

Shrinkage Rule. For the molding dimensions of a pattern or 
core box a shrinkage rule must be used. The reasons are that when 
a mold made from the wooden pattern is filled with molten metal 
its temperature is very high, and as it cools and solidifies it con- 




Fig. GO Standard Folding TJule 

tracts. Accordingly, to compensate for this, the pattern maker 
must add to the size of the pattern. In order that this may be 
done, and exact relations nevertheless be maintained for all dimen- 
sions, a shrinkage rule is used. This rule is marked off exactly like 
an ordinary rule, but if the two are compared, the shrinkage rule 
will be found to be about | inch longer than the other for each foot 
of length. 



PATTERN MAKING 



29 



The contraction or shrinkage of different metals in the molds 
varies greatly ; that for cast iron bemg, as above stated, J inch to each 
foot. For brass, however, the shrinkage is ^ inch to the foot ; and for 
many of the softer metals it is as great as J inch per foot. 

Shrinkage rules, Fig. 61, are usually made of a single piece of 
boxwood or beech; those for cast iron being 24| inches long, for 



TTTTmr 



J6 IN. PER FT. SHRINKAGE 



^^ 



TntTTTT 



1 1 Ml I III 



:k 



iiiliiiilniiMiii 




Fig. 61. Shrinkage Rule 

brass 24f inches long, and for other soft metals 24^ inches in length. 
They can also be bought made of tempered steel 12| inches, 12 j^ 
inches, and 12| inches in length. In making use of the shrinkage 
rule, the workman will proceed just as though he were using a 
standard rule; and when the pattern is completed it will be found 
to be larger in all its dimensions, just in proportion as the extra 
length of the shrinkage rule makes it greater than the stand- 
ard rule. 




.-Ifllfc 



:iffT!fix -. 



Iiijlilliiiliiiliiiliiiliiilililiiilililiiiliiil 



Fig. 62. Improved Marking Gage 

Marking Tools. Marking Gage. The marking gage is used for 
drawing a line at a given distance from, and parallel to, the already 
trued and jointed surface or edge of a board or piece of wood that is 
being marked to dimensions. 

There are many forms of this tool, but in the improved gage, 
illustrated in Fig. 62, the head is reversible. The flat side of the 
head is used for ordinary straight work, while the reverse side, hav- 



30 



PATTERN MAKING 



ing the brass face with two projecting ribs, enables the operator to 
run a gage line with perfect steadiness and accuracy around curves 
of any radius, either convex or concave — a feature much to be 
desired in a pattern-maker's gage. 

Dividers.- The ordinary woodworker's dividers can be bought 
in many forms, the most common being the screw-adjusting wing 
dividers shown in Fig. 63. This form is reliable, and is easily 
adjusted to the required distance between points. Moreover, when 




Fig. 63. Common Wing Dividers 




Fig. 64. Removable- 
Point Dividers 



clamped by the thumbscrew, it is not liable to be altered by a slight 
blow in handling. 

Another and improved form is shown in Fig. 64, one leg of 
which is removable so that a pencil can be inserted. This will 
be found very convenient for marking and laying out work. 

For spacing the teeth of gear wheels, and for other work in 
which great accuracy is required, a pair of 2|-inch or 3-inch dividers, 
such as are shown in Fig. 65, will be found necessary. 

Trammel. The trammel is used when the distance between 
the points to be reached is too great for the ordinary dividers. The 
trammel points are clamped to a beam of sufficient length to enable 
them to be set the required distance apart. They may be bought 



PATTERN MAKING 



31 



plain, as in Fig. 66, or with one point adjustable, as in Fig. 67. The 
points are removable for the insertion of a pencil socket and pencil 
when needed. 

Fo;- very accurate work, an excellent tool of this kind is illus- 
trated in Fig. 68. The beams furnished are 4 inches and 13 inches 
in length. By the use of the cone center V, which may be sub- 
stituted for the regular point center, 
the tool can be used for scribing a 
line around any hole already bored 
— sometimes a matter of great con- 
venience. The complete set includes 





Fig. 65. Brown and Sharpe Fig. 66. Plain Trammel Points 

Spring-Joint Dividers 

the pen, pencil, straight and bent points, and the cone center, as 
shown in the cut. 

Calipers. Calipers, like dividers, are made in many different 
forms with and without screw adjustment. Fig. 69 illustrates 
the screw-adjusting wing calipers for outside measurements, and 
Fig. 70 shows the firm-joint outside calipers used for the same 
purpose. Inside calipers for taking inside dimensions and inside 
distances are shown in Fig. 71, and the adjustable inside calipers 
are illustrated in Fig. 72. 

Calipers are used for measuring the distances between points 
external and internal when a rule could not be used with accuracy. 



32 



PATTERN MAKING 



They are indispensable to the wood turner for measuring the diam- 
eters of cylindrical forms and other work while being turned to 




Fig. 67 Trammel with Adjustable Points 



Fig. 68. Accurate Trammel Set 





Fig. 69. Wing Calipers 



Fig. 70 Firm-Jomt Calipers 



required dimensions in the lathe. When used by the pattern maker, 
they may be applied while tbe wood is revolving, until it has been 



PATTERN MAKING 



3? 



reduced almost to the required dimensions; after which, when the 
calipers are used, the lathe should be stopped to prevent the sur- 
face from being marked by the points, and in order to obtain exact 
measurements. The calipers should not be pushed or forced over 
the piece, but in passing over the finished cylinder, the points should 





Fig. 71. Inside 
Calipers 



Fig. 72. Adjustable 
Inside Calipers 



touch it lightly without springing the legs of the calipers; other- 
wise, the required dimensions cannot be obtained with accuracy. 

MISCELLANEOUS SMALL TOOLS 



Forcing Tools. Hammer and Mallei, There remain to be 
described a few tools, which, while necessary, are so common as 
hardly to require either illustration or description. Among these 
are the hammer, the best form of which for the pattern maker is 
shown in Fig. 73, and the mallet, of which the best form is shown 
in Fig. 74. 

A mallet that is to be used on the handle of firmer chisels and 
other pattern-maker's tools, should not be made of hickory or of 
lignum-vitae, nor have hard-rubber or hard-fiber facing. Mallets 



34 



PATTERN MAKING 



thus made soon mar, splinter, and destroy the tool handles on 
which they are used. Beechwood and maple furnish the best 
material for mallet heads for the use of the woodworker who works 




Fig. 73. Typical Pattern Maker's Hammer 



in pine and other soft woods. It is true that the mallet head will 
not last so long if made of beech or maple wood, but the chisel and 

gouge handles will be 
protected, which is a 
matter of much greater 
importance. 

Screwdriver and A2vls. 
Of the screwdriver, illus- 
trated in Fig. 75, at least 
two or three sizes will be 
found necessary. 




Fig. 74. Mallet 



iri3n> 



Fig. 



Ordinary Screwdriver 



^^=0 



The scratch awl. Fig. 76 — although but little employed at the 

work bench, where a knife is 
used in its place for all accu- 
rate markings — is indispen- 
sable to the pattern maker for 
laying out the dimensions on his work while it is revolving in the 
turning lathe. It should be long and slender, as shown, and is used 
on the revolving wood by placing it over the required graduation of 
the rule, while the latter is held on the tool rest. 



Fig. 7G. Scratch Awl 



PATTERN MAKING 



35 



Brads and small wire nails must often be driven at such an 
angle to the grain of the wood, or in such a position, as to make 
it necessary first to bore 
a small hole in order 
to start the brad in the 
required direction. The 
brad awl, illustrated in 
Fig. 77, is a convenient 
tool for this purpose. It is commonly ground to a chisel point, as 
shown at a, but will be less liable to cause splitting, and will work 




Fig. 77. Brad Awl 




Fig. 78. Side-Cutting Pliers 



faster and with greater ease, if ground to a double spear point, as 
shown at b. The four corners, if kept sharp, will enter the wood 
and cut faster than the chisel point. 




Fig 79. Wooden Clamp 



Pliers and Clamps. Side-cutting pliers, such as are illustrated 
in Fig. 78, will be found convenient not only for cutting off wire 




36 PATTERN MAKING 

and brads, but for removing small brads and for holding small pieces 
whik being worked to shape. 

Every pattern shop should have at least one dozen each of 
three or four different sizes of hand screws or clamps similar to 
that shown in Fig. 79. These are adjustable through wide ranges. 
They are used for clamping together the material that is being 
glued up to form the different parts of a pattern, and are convenient 
also for many other purposes. The all-iron C-clamp, shown in 
Fig. 80, is sometimes useful in positions that are hard to reach 

with a hand screw. The 
method of adjusting and 
of using the hand screw 
will be fully explained 
later. 

Abrading Tools. 
Wood Files. The half- 
round cabinet file and 
half-round cabinet rasp. 

Fig. SO. Iron Clamp . . _. ^ 

shown m Fig. 81, enter 
largely into the work of the pattern maker, and should be bought 
in sizes each of G inches, 8 inches, and 10 inches. Larger as well 
as intermediate sizes may often be found necessar}', but will not 
be needed for ordinary work. 

Oil Stones and Slips. As before stated, new planes, chisels,- and 
other edged tools, if of the best quality, are always sold ground and 
sharpened, ready for use. ^Yhen used, however, they soon become 
dulled, and must then be resharpened, and be so kept as to have a 
smooth keen cutting edge in order to do good work and to work 
rapidly. The method employed for doing this is the same for all 
edged tools, whether ground and sharpened on one side or on 
both sides. 

Oil stones are used for plane irons, chisels, and all flat and 
straightedged tools; and oil slips, having rounded edges, are used 
for gouges, and for all tools having curved edges. They are made of 
different sizes, and may be found of many and widely different 
qualities. The best known and most widely used oil stones in this 
country, and perhaps in the world, are the Washita, of which the 
Lily White Washita brand, being carefully selected, is the most 



PATTERN MAKING 



37 



even in grade and quality, and is the best-adapted natural stone 

for woodworkers' tools. For wood-turners' and pattern-makers' 

tools, the sharpening qualities of the ^^^^ZHZ^ 

Washita are unsurpassed; but the quality '^^^IZI^ 

differs greatly in stones sold under this 

name, some being uneven in hardness, and 

some soft and worthless. No trouble will 

be found, however, if some well selected 

brand such as the one mentioned above 

is chosen. 

The Arkansas oil stones are claimed to 
be the hardest and finest oil stones in the 
world. They are composed of nearly pure 
silica in the form of minute crystals inter- 
penetrating one another, and differ from 
the Washita only in the minuteness of the 
crystals and in their more compact arrange- 
ment. They are consequently very much 
harder, and cut hardened steel more slowly 
than coarser grades of stone, but impart a 
finer and smoother edge to the tool. They 
are used by wood carvers, engravers, watch- 
makers, and others using tools that require 
a very fine edge or point. They are expen- 
sive, and should be used carefully with equal 
parts of sperm oil and glycerine. 

A good size for an oil stone is 6 inches 
to 8 inches in length, and from If inches to 
2 inches in width. The thickness does not 
matter, but the stones usually vary from 
f inch to 1| inches in thickness. The oil 
slip should be about 4J inches in length, 
and from If inches to 2 inches in width, 
tapering from | inch on one edge to -^ inch 
on the other, both edges being rounded as 
shown in Fig. 82. and Rasp 

In using the oil stone, care should be taken to hold the bevel of 
the tool flat, or nearly flat, on the stone, so that the cutting edge may 







Fig. 81. Cabinet File 



38 



PATTERN MAKING 



be kept thin and in easy working condition. The stone is held 
stationary on the work bench, and the tool is moved forward and 
backward over its face. In the use of the oil slip, on the other hand, 




Fig. f 2. Oil Slip 

the tool is held stationary, with the cutting edge or end up, and the 
slip is rubbed over the beveled surface with a circular motion or 
stroke, until a keen sharp edge has again been imparted to it. An 
abundance of oil should always be used in order that a finer and 
smoother edge may be given to the tool, and the pores of the stone 
be kept clean and free from glazing. 

In the last few years an entirely new variety of oil stone and 
oil slip has been placed on the market. It is called the India oil 

stone, and is made from corundum, the 

hardest of all mineral substances except 
the diamond. These stones have wonderful 
cutting qualities, and differ greatly from 
other oil stones in that they cut steel 
much faster, impart better edges, and do 
not glaze. They are also of uniform 
texture throughout. India oil stones are 
^^^ /"^v^ furnished in three grades — coarse, medium, 

/ \^ K^^ and fine — and in all required shapes, a few 

of which are shown in Fig. 83. Only the 
fine stones are adapted for woodworking 
tools and for those classes of tools requir- 
ing a fine cutting edge. 

Grindstones, Second in importance 
to a good oil stone is the grindstone, 
power driven if possible. It should not 
be too close-grained. A rapid cutting stone, even if moderately 
coarse, is greatly to be preferred, as all ground edges must be finally 
finished on the oil stone however finely they may have been ground 
on the grindstone. A stone about 36 inches in diameter when new. 



^ Oi 




Fig. 83. Shapes of Oil Stones 




PATTERN MAKING 39 

Is a good size, and can be bought with a suitable cast-iron trough 
underneath, and also with an arrangement for supplying th^ water 
necessary to keep the stone wet. 

In all stones there will be found great differences of hardness 
in different parts* Stones soon lose their cylindrical shape and 
must be turned true. A piece of gas pipe or an old file will be 
found excellent tools for this purpose, but they must be used 
without water. 

In using the grindstone for plane irons, chisels, and other tools 
that must be ground with a long bevel or to a thin edge, it is better 
to stand so that the stone runs toward 
the cutting edge of the tool, as shown 
in Fig. 84. This position grinds the 
tool much faster, and less of a feather 
will be turned up on the final edge. pig. 84. Grinding Long Bevei 
Scraping tools, however, and indeed all 

tools having a very short bevel, or whose edges are ground to a very 
obtuse angle, may be held so that the stone will revolve away from 
the cutting edge of the tool, this position being less liable to cut 
hollows in the face of the stone. This method of grinding, however, 
is too slow for tools having a long bevel, and which for that reason 
require more grinding. 

When to use the grindstone is a question that often occurs to 
the beginner, who sometimes confuses the use of the grindstone with 
that of the oil stone. The grind- 
stone is not in any sense an instru- \ ^ ^"-"^^^ 

ment for sharpening woodworkers' ^ 

tools. When a chisel or a plane L__— ^ 

iron has been sharpened on the oil ^g. 85. sharp and Wom Bevels 

stone for several successive times, 

the bevel is gradually worn shorter, and its shape changed from 
that shown at a, Fig. 85, to a shape similar to that shown 
at 6, When the length of the bevel is thus reduced, the angle of 
the cutting edge is too obtuse to do good work or to work easily. 
The metal at c must then be ground off on the grindstone, and 
the bevel of the tool restored to its former correct shape, as shown 
at a, after which the cutting edge must be sharpened and finished 
on the oil stone. 



40 



PATTERN MAKING 



A\ACHINE TOOLS 

Turning Equipment. Of all power-driven machines, the roost 
indispensable to the pattern maker is the wood-tm-ning lathe. In 
a small shop where small patterns only are made, a 14-inch or a 
16-inch speed lathe, such as is shown in Fig. 86, may prove sufficient 
for all purposes; but if only one lathe can be afforded, it should be a 
regular pattern-maker's lathe, similar to that illustrated in Fig. 87. 

Paftcni'Mal-er^s Lathe. The pattern-maker's lathe differs from 
the speed lathe in that the headstock spindle extends through the 




Fig. 8G. Speed Lathe 



left-hand bearing, and is fitted to receive faceplates and chucks the 
same as on the inside end. The arrangement of the countershaft 
is also such as to give a much wider range of speed to the lathe head, 
so that pieces of very large diameter may be turned at a speed pro- 
portioned to their sizes. These lathes are also fitted with a hand- 
feed slide rest — either compound, as shown in the illustration, or a 
plain sliding tool holder moved by a rack and pinion, as may be 



PATTERN MAKING 



41 



desired. The tailstock is arranged with a cross adjustment to facili- 
tate turning long cylinders tapering if required. When not in use 
the slide rest may be removed from the lathe, and the ordinary tool 
rest and rest socket substituted in its place for hand-turning. The 
speed at which a lathe should be run is always indicated by the 
manufacturer, the countershaft usually running at a speed pf 500 
to 550 revolutions per minute. 

Chucks and Faceplates. A variety of chucks and faceplates for 
holding the work are always furnished with a lathe. Some of these 
are shown in the engraving, the screw chuck being shown at a, 




Fig. 87. Pattern Maker's Lathe 



Fig. 87, and two of the iron faceplates are shown, one on each end of 
the spindle. 

In addition to these faceplates, which really form the base 
only for chucking the pattern, wooden chucks must be used between 
the iron faceplate and the pattern. These wooden faceplates are 
constructed in a variety of ways by different pattern makers; but 
for small patterns it is necessary to use only a plain board { inch to 
\\ inches thick, of a slightly greater diameter than the required 
pattern, and screwed fast to the iron faceplate, as shown in Fig- 88. 
To this, after being placed in the lathe and turned true, the pattern 
is attached, as will be fully illustrated and described farther on. For 
patterns of a medium size, say 20 inches to 30 inches in diameter, 



42 



PATTERN .MAKING 




Fig. SS. Construction of Small Fac( 



the board should be stiffened by means of a wide wooden bar firmly 
screwed across the back, as in Fig. 89. 

\Mien needed for very large or heavy work, the chuck, in order 
to pre\'ent vibration, must be strong in proportion. It is best made 

as illustrated in -Pig. 90, in 
which the front of the chuck, 
as shown at a, will be least 
affected by the moisture in the 
air if left unglued, or at best 
only tongued and grooved, 
being held together by the 
crossbars only, as shown at b, 
to which it is firmly screwed, 
without glue. This chuck is 
simple and cheap, and will be found in practice much stronger and 
more rigid than one built up of sectors or in a more elaborate way. 
Turning Gouge. Of lathe hand tools the first to be considered, 
as also the first to be used, is the gouge. It is used for reducing the 
stock to be turned, from a rough or rectangular shape to a cylindrical 
form, preparatory to smoothing and finishing. It is ground and 
beveled on the back or convex side, and the shape of the cutting edge 
should be of the same curvature as the inside, or upper side, of the 

tool. Gouges are made in 
all sizes, one of which is 
illustrated in Fig. 91; but 
for the pattern maker's use 
four gouges, ranging from 
-J- inch to Ij inches, will 
be found sufficient for all 
purposes. 

Before using the gouge, 
and indeed any lathe cut- 
ting tool, the workman 
should take care to see that 
the tool rest has been elevated above the center line of the lathe cen- 
ters, from I inch for small work, to 1 inch or more for large work. 
The position of the gouge, when in use, is horizontal and at about 
ii right angle to the tool rest. It should not, however, be laid on 




Fig. 89. Medium-Sized Faceplate Construction 



PATTERN MAKING 



43 



the rest so as to use only the extreme point of the tool, but should be 
tilted over, first to one side and then to the other, so as to bring all 




Fig. 90. Strongly Braced Faceplate for Large Work 

parts of the cutting edge, successively, in contact with the wood that 
is being turned. 

The gouge may be used by tlie beginner without hesitation, 
as in no position, whether tilted or on its back, will it catch or rip 
into the wood. The tool should be held firmly by the extreme end 
of the handle, in the right hand, while the left hand rests against 



=ar 



^ 



Fig. 91. Turning Gouge 

the tool rest, the blade of the tool being grasped lightly with the 
fingers, and passing through and under the left hand while resting 
on the tool rest, 

Sheno Chucl. As the turning gouge— being curved—can be used 
pnly as a roughing-down tool or for turning out hollows, and cannot 




Fig. 92. ^kew Chisel 



be used for finishing, the skew chisel, one size of which is shown in 
Fig, ^3, is used, in common and ornamental turning to mal^e a 



44 PATTERN MAKING 

straight, true, or smooth surface. This form of chisel is made in 
all sizes from. J inch to 2| inches in width, but, unlike the gouge, 
requires considerable practice and skill for its successful use. 

The skew chisel is held slightly tilted in order that while the 
short edge of the blade touches the tool rest, the long edge will be 
slightly above [the rest, so that the long 
corner of the skew point extends up and 
well over the cylinder which is being 
smoothed, thus preventing the long skew 
point from catching and tearing into the 
work. All the cutting must be done with 
the short part of the skew edge, say J inch 
only of the cutting edge, the tool resting 
not only on the tool rest, but resting also 
firmly on the cylinder that is being turned, 
just as a plane rests on a board while cut- 
ting and removing the shavings from its 
surface. The right position for this tool is hard to obtain at first, 
and can be acquired only by patient and continued practice. In no 
case, however, should the skew chisel be held flat on the tool rest, or 
used as a scraper, this not being allowable or good practice either in 
common or in ornamental turning. One skew chisel each of the 
J-inch, ^-inch, 1-inch, and U-inch sizes will be found sufficient for 
all ordinary work. 

Scraping Tools. While the skew chisel works with great rapid- 
ity and does smooth and very satisfactory work in all kinds of orna- 



\ 


Right 
Skew- 
Left 
Skew 

Spear 
Point 

Round 
Point 




/ 




> 




) 


■ 




Square 
Point 


Fig. 93. Scraping 
Tools 





^ 



Fig. 94. Cutting-Off Tool 

mental turning, the dimensions obtained with this tool are not so 
accurate for pattern work as those obtained by the regular pattern 
maker's scraping tools. These tools, whatever may be the shape of 
the points or cutting edges, are all flat like the skew chisel, and are 
ground or beveled on one side only. Indeed there is no better wide 
scraping tool for large surfaces than a common firmer chisel after it 
has been worn short so as to be free from vibration. 



PATTERN MAKING 



45 





n 






? . I 



=£^.=. 



^ 



i I 



Fig. 95. Two Views of Circular-Saw Bent^h 



46 



PATTERN MAKING 



Scraping tools are made in many forms and shapes, and are 
ground by the workman to suit the requirements of his work. A 
few of the many shapes in common use are illustrated in Fig. 93. 

These tools should be ground with a very short bevel, and 
must be sharpened much oftener than a cutting tool. The revolv- 
ing wood, passing at right angles to the sharp edge, wears it away 
more quickly than it can a cutting tool, for the latter is also .worn 
away on the slanting side of the bevel. 

CuUing-Off Tool. A very necessary tool for all kinds of wood 
turning is the parting or cutting-off tool, shown in Fig. 94. This is 
used as a scraping tool for cutting recesses in the work and for cut- 
ting off finished work from the faceplate, and will also be found 
useful for many other purposes. 

Sawing Machines. Circular Saw. As a time-saving and labor- 
savmg machine a good circular-saw bench is necessary in every well- 
equipped pattern shop, and 
is unsurpassed in capacity 
and in the variety of work 
for which it may be used. 
As shown in one of the views 
in Fig. 95, it is permanently 
provided with two saw arbors 
one carrying a rip saw and 
the other a crosscut saw, 
either of which may be raised 
easily and quickly to cutting 
position, the other being 
depressed at the same time. 
The front half of the table is 
made to slide, while the whole 
table can be tilted to an 
angle of 45 degrees, and will remain in any position desired without 
clam-ping= As shown, it is provided with adjustable gages for cross- 
cutting or mitering, and with an adjustable fence for ripping, all of 
which are removable at will, leaving the whole upper surface of 
the table clear. -Fig. 96 gives a view of the table from above. As 
in the case of the turning lathe, the intended speed of the saw coun- 
tershaft is indicated by the manufacturer. 




Fig. 06. Plan of J5aw Tabl< 



PATTERN MAKING 47 

The single-arbor circular-saw bench, shown in Fig. 97, is a less 
expensive machine than that just described; but the time lost in 
having continually to change the saw on the single arbor from rip 
to crosscut and back again for pattern work is a very annoying as 
well as expensive inconvenience. 

Band Saw, A good band saw, such as the one illustrated in 
Fig. 98, is indispensable for cutting the curves and irregular shapes 
that form a part of so many patterns. The best machines of this 




Fig. 97. Single-Arbar Saw Bench 

description have a tilting table which can be set and clamped at any 
angle, enabling the workman to give the required bevel or draft to 
his work. 

With a sharp and well-kept saw, there is no more rapid or 
correct method of cutting out and making circular core boxes of all 
sizes whose length is within the capacity of the machine. The 
block from which the core box is to be made must be cut perfectly 
square on the end which is to rest on the saw table, and, if this end 
of the block is not large enough to give sufficient base to hold it in 
an upright position, the block can be supported against the blade of 



48 



PATTERN MAKING 



a try-square, or, better still, against a wooden bracket made for the 
purpose. 

Scroll Saw. The scroll saw, illustrated in Fig. 99, is necessary 
for cutting inside curves and openings in which a band saw could 
not be used. Like the band saw, it should have a tilting table. 
Where both saws cannot be afforded, the scroll saw takes the place 
of both. While not working so rapidly as the continuously cutting 

blade of the band saw, it is, 
when kept sharp and in good 
running condition, a great 
time- and labor-saving ma- 
chine. 

Planers. Because of the 
fact that pattern lumber can 
be bought already dressed 
to any required thickness, a 
planing machine is not found 
in every pattern shop. The 
ordinary surface planer, how- 
ever, will not take out the 
twist, or wind (i as in find), 
and the curves from the sur- 
face of the lumber — a matter 
of very great importance in 
pattern work, and one which 
requires a great deal of time 
if the planing is done by 
hand. 

Hand Planer and Jointer. 
The hand planer and jointer, 
illustrated in Fig. 100, is almost indispensable, not only for facing the 
sides of the boards perfectly true, straight, and free from wind, but 
also for jointing the edges, and for making perfectly fitting glue 
joints in a manner superior to any hand work. These machines can 
be bought in widths of from 12 to 30 inches. A machine 16 inches 
wide is a very desirable size for pattern work. 

It will readily be seen that the running of a board over the hand 
planer, while facing the surface straight and true, will not reduce 




Fig. 98. Band Saw 



PATTERN MAKING 



49 



the piece to a uniform thickness. To avoid the necessity for much 
hand work in accomplishing this result, first face the piece on the 
hand planer sa as to make one true side, and then run it through a 
surface planer similar to the one illiistrated in Fig. 101. If they can 
be afforded, both of these machines, especially the hand planer, will 
return large profits on the money 
invested in them, because of 
the time and labor saved and 
the superior quaUty of the work 
done. 

Trimmers. Among the 
many labor-saving tools of late 
years, there is perhaps none 
more popular and none more 
indispensable in a pattern shop 
than the universal wood trim- 
mer. It will cut any end or 
angle within the capacity of the 
machine; and an end which 
would take from 10 to 15 minutes 
to square and true up correctly 
by hand, with square and plane 
or chisel, can be finished in as 
many seconds with this tool. 
It is made in many sizes, from 
the small bench trimmer, two 
views of which are shown in 
Fig. 102, to the large machine 
illustrated in Fig. 103. The 
small No. machine, shown in 
Fig. 102, cutting to 6 inches 
wide and 3 inches high, is so 
comparatively inexpensive— considering the time it will save and the 
quality of the work produced— that it should be on the bench of 
every pattern maker. The larger machine will cut 20| inches wide 
and to a height of 7| inches. These machines will cut the acute 
angles between 45 degrees and 90 degrees, and the obtuse angles 
between 90 degrees and 135 degrees. 




Fig. 99. Scroll Saw 



50 



PATTERN MAKING 




Fig. 100. Hand Planer and Jointer 



3 





Fig. 102, Front and Rear Views of Bench Trimmer 



PATTERN MAKING 



01 




Fig. 103. Universal Trimmer 



52 



PATTERN MAKING 



ALLOWANCES IN CONSTRUCTION 
MOLDING PRACTICE 
General Molding. As has already been said, it is necessary 
that the pattern maker should have some knowledge of molding 
in order that he may construct his patterns so that they can easily 
be removed from the sand. A brief description of the general 
method employed will suffice. 

Use of Flask, Ordinarily, a casting is made in a flask, con- 
sisting of two parts, each containing its complement of sand — the 

upper part called the cope, and 
the lower part the nowel or drag. 

. '-^fst -V r. ^ fe*^"^^ The pattern is sometimes made in 

L m , . LiJ ^ J two pieces that separate or part 

along the line separating the cope 
and the drag. Thus, in Fig. 104 
the pattern separates with the flask on the line A B, and, when 
so separated, the cope is turned upside down, and the portion C 
of the pattern is lifted out. The portion D is lifted out of the drag 
in the same way. 

Cores for Holloiv Castings, In the case of molding a hollow 
object, the internal cavity in the casting is formed by means of a 
dry-sand core which rests in impressions made in the sand by core 
prints attached to, and forming a part of, the pattern. 

To illustrate this, let it be required to cast the hollow^ cylinder 
shown in Fig. 105. The wooden pattern necessary to produce this 




Fig. 1*'^. Flask Showing Parting 




Fig. 105. Hollow Cylinder 



Fig. 106. Cylinder Split Pattern with 
Core Prints 



hollow cylinder is shown in Fig. 106, which, as wdll be seen, repre- 
sents the cylinder only externally by the part A, The core prints, 
one on each end of A, are represented by x and y. These projections 
form part of the pattern, and make their impressions in the sand 
with the part Aj Avhich alone represents the required cylinder. 
For making the Core, the length of the inside of the core box, in 



PATTERN MAKING 



53 




Fig. 107. Half-Core Box 




which the dry-sand core is formed, will be the extreme length of 
the pattern including x and y^ and the inside width will be the exact 
diameter of the core prints. In this case, the core being a cylinder, 
only a half -core box, Fig. 107, is 
used. In it are made two semi- 
cylindrical cores, which, after being 
dried, are cemented together, thus 
forming the complete cylindrical 
core required. 

Molding Split Pattern* To mold 
this halved or split pattern, as it 
is called, the upper half of the pattern is laid on the molding 
board, and the drag is turned over it with the bottom side of the 
drag up and the parting side on the molding board, as shown in 
Fig. 108. After being rammed up, 
the drag and molding board are 
turned over and the board removed, 
when the parting of the pattern is 
exposed, the half-pattern being im- 
bedded in the sand. 

The second half of the pattern 
is now placed in position on the first, and dry parting sand is 
spread over the surface of the wet or green sand; the cope is put 
in position on the drag, as shown in Fig. 109, and rammed up. 
Upon the cope and the drag being r?-, 
separated, the sand separates on 
the line to which the parting sand 
has been applied, which, as may 
be seen, is the line of parting of 
the cope and the drag, one-half 
of the pattern remaining in each. 

After the halves of the pat- 
tern have been removed from the 
cope and from the drag, respec- 
tively, the completed dry-sand core is placed in the molds made 
by the core prints x and y. This core B is shown in position 
in Fig. 110, and entirely fills the parts of the mold made by x 
and ?/, leaving between itself and the surface of the mold made 



Fig. 108. Starting SpUt-Pattern Mold 




Fig. 109. Position for Molding Cope 



54 



PATTERN MAKING 



by A room for the metal to be poured which is to form the required 
cylinder. 

Coping Out for Solid Patterns* Simple Cylinder, In molding 
the above cylinder it is not necessary that the pattern should be 




Fig. 110. Completed Mold with Core in Place 



parted — ^made in two halves — as shown in Fig. 106. Patterns for 
small work, and even for large castings, are often made in one piece, 
as shown in Fig. HI. To mold this solid pattern it is placed on the 




Fig. 111. Solid Pattern for Cylinder 



molding board with sufficient sand to keep it from rolling, and the 
drag is inverted over it as before. AYhen the drag has been rammed 
up, it is turned over, and will then present the appearance shown 




--';-^ 



i^ 




Fig. 112. Solid Pattern Rammed in Drag Fig. 113. Coped-Out Mold for Solid Patterns 

in Fig. 112, the entire pattern being embedded in the sand. The 
sand is now cut away and removed, as shown in Fig. 113, down 
to the center line of the pattern. The cut sand is smoothed; and, 
after dry parting sand has been applied to the surface of the wet 



PATTERN MAKING 



55 



sand, the cope is placed in position and rammed up as usual. Upon 
the cope being removed, the sand will part along the lines de and 
cd, leaving one-half of the 



entire pattern exposed. The 
pattern can now be lifted out, 
the core placed in position, 
and the cope returned to its 
place on the drag, when it is 
ready for the pouring, as in 
Fig. 110. 

Spoked Wheel, Another 
example of a one-piece pattern 

is the small brass hand wheel pig. 114. Hand wheel 

shown in Fig. 114. The pat- 
tern for this wheel is placed on the molding board, and the drag 
inverted over it and rammed up. After the drag has been turned 











Fig. 115. Wheel Mold Coped Out 

over, the sand is cut away and removed, not only down to the 

center of the rim, but also to the center line of the four arms, as 

shown by the dotted hues in Fig. 115. All cut surfaces of the sand 

are smoothed, parting sand 

is sprinkled over the parting 

thus made, and the cope is 

placed in position and 

rammed up. When the cope 

is lifted off, the sand will 

part half way down on the 

arms and rim, aUowing the 

pattern to be taken out 

easily. 

Perforated Journal Cap. 
Still another example in 




Fig. 116. Journal-Box Cap 



56 



PATTERN MAKING 



which a single-piece pattern can be used, is shown in the journal-box 
cap illustrated in Fig. 116. A cross-section of the pattern through two 
of the bolt-hole core prints is shown in Fig. 117. The pattern is 
placed on the molding board in the inverted drag, and is rammed 




mm 


i 


m 


m 


^H 


y^M 


'^'' '■.'•' 









Fig. 117 Cross-Section of Cap 
Pattern 



Fig. 118, Cap Rammed in Drag 



up as usual. When the drag is turned over, the position of- the 
pattern in the sand is as shown in cross-section in Fig. 118. The 
sand that may have entered the curve cde is lifted out, and the 
necessary draft is given to the sand at the two ends of the opening 
cde, as shown at a, Fig. 119. The cope is next placed in position, 
and when this has been rammed up and lifted off, the sand lying in 




Fig. 119. Coped-Out Mold for Cap 

the curve cde will be lifted with it. The pattern is now removed, 
the bolt-hole cores are placed in position, and the cope is returned 
to its place on the drag. 

In this case the core prints should be in length at least twice 
the thickness of the metal through which the hole is to be cast, 
and the length of the cores will be equal to the thickness of the metal 
plus the length of the prints. 



PATTERN MAKING 



57 



Molding Difficult Patterns. Use of Green-Sand Ring, In the 
small sheave pulley. Fig. 120, we have an example of a casting the 
construction of the pattern for which, so as to make it easily 




Fig. 120. Sheave TwWey 

.removable from the sand, may give some trouble to the beginner. 
The pattern is shown in cross-section in Fig. 121, and is molded in 
a two-part flask. At first 
it would seem impossible 
to place the pattern in the 
sand so that either half 
could be removed when the 
cope and drag are separated on the parting line of the pat- 
tern. This is readily accomplished, however, as follows: 

The half pattern C is placed in the inverted drag, with the 
parting downward on the molding board, and is rammed up in the 



Fig. 121. Pulley Split Pattern 




Fig. 122. Piilley Mold Coped-Out for Ring 



usual way. After the drag is turned over, the sand is cut away 
and removed to the center of the rim edge, as shown in Fig. 122. 
The cut is carefully smoothed, and parting sand applied to the 



58 



PATTERN MAKING 



cut surface. The part a of the pattern is placed in position on c, 
and is rammed up carefully, the sand being then cut away to the 




Fig. 123. Green-Sand Ring in Split-Pattern Mold 

center of the rim edge of A, Parting sand is applied to the new 
surface, after which the cope is placed in position and rammed up. 

When the cope and 
drag have been separated, 
the upper half A of the 
pattern is taken out, and 
the cope is returned to 
its place on the drag. The 
whole flask is now turned 
over, and the drag lifted 
off the cope, when the 
ring of green sand Z, 
Fig. 123, will rest on the 

Fig. 121. Dovetailed Slide i i ^i 

cope sand and the part 
C of the pattern is taken out. We thus have two partings of the 
sand mold, but only one parting of the flask. 




"Z&ni 



r^ 



r^ 



125. Loose-Piece Pattern 



Fig. 126. Loose Pieces in Mold 



Many other examples might be given, as the case of the common 
two-flange pulley, which, when small, is often molded in this way. 



PATTERN MAKING 



59 



Loose' Piece Patterns, It is frequently the case that parts of 
the pattern will overhang so that the pattern cannot be removed 
from the sand in any direction, even if parted. In such cases the 




■ice; 




Fig. 127. Turbine Case 



w/yy^yyyyy>^/y/^^7??^^ 




wz/y/Zy'// 



Overhanging parts are fastened loosely to the main part of the pat- 
tern by wires or wooden pins. An example of such a casting is shown 
in the slide, Fig. 124. A cross-section of the pattern for this sHde 
is shown in Fig. 125, in which the two overhanging parts are held 
in position by the use of 
pins. After being rammed 
up, the part A is removed, 
leaving the parts b and c 
still in their positions in the 
sand, as shown in Fig. 126, 
These may now be care- ^''■'''- s-tion of casting. Fig. 127 

fully removed toward the center of the opening and lifted out. 
Use of Dry-Sand Cores, In some cases there is not sufficient 
room, when the main part of the pattern has been taken from the 



m 



mm 




60 



PATTERN MAKING 



mold, to remove the projecting pieces. In such cases, the over- 
hanging pieces or projections must be made by using dry-sand 
cores. To illustrate this, we shall consider the pattern for'the small 

cast-iron turbine case illus- 
\v^.uiAw^i^^^JZ'3^j^^^^^jj^^^jjj^j/^^j^s7^ trated in Fig. 127. 

A section view or the 



-Rim Iron or Wood Pattern 



J H 

Fig. 129. Section of Rim and Top, Fig. 127 



casting through the line 
A By Fig. 127, is given in 
Fig. 128. The mold is parted 
on the level cc, and the 
boss, and the inside and the 
outside flanges, will be made 
with dry-sand cores, the 
three core boxes being shown in Fig. 130. The boxes shown at /i 
and I have their nearer ends removed so as to illustrate the 
internal construction. 

Fig. 129 illustrates a section view of the rim g, and the top 
outside flange and web patterns e. The boss a, however, w^ould 

prevent the pattern 
from being removed 
from the mold, and 
even if a were made 
loose it could not be 
taken out through the 
narrow space made by 
the thin side of the 
pattern g. To over- 
come this difficulty the 
boss a is made in the 
core box Z and the core 
is bedded in, as shown 
atHnFig. 131. 

Referring to Fig. 
131, which is a section 
through the vertical center of the pattern, the molding process is as 
follows: A level bed dd\^ struck off, and the core t is located on this 
bed or surface at the center of the flask. Over this core are placed the 
rim g and the required number of outer-flange cores made in core box 




Fig. 130. Core Boxes for Fig. 127 



PATTERN MAKING 



61 



h. The core for the lug a is next put i nto its proper location, shown at 
If and the mold is rammed to the top of the rim pattern. The sand 
inside the rim pattern is struck off leVel, and the web e is placed 
in position and rammed down so as to fit the rim into the groove 
on the under side of the web. The mold is now filled level with the 
upper side of the web cc and the parting made. The cope mold 
is now made, and, after being removed, the pattern is drawn. The 
disk e is removed first, and then the rim g, when it will be seen that 
these dry-sand cores, in connection with the pattern, form a mold 
which. will give the casting required. 

Examples in molding practice could be multiplied indefinitely, 
but the foregoing, we think, will give such suggestions as will enable 




Fig. 131. Section through Vertical Center of Pattern for Fig. 127 

the beginner in pattern making to construct all ordinary patterns 
so that they can easily be removed from the sand without injury 
to the mold. 

USE OF DRAWINGS 

Construction Conditions. As already explained, the pattern 
maker must understand working drawings in order to construct 
patterns from them directly. These drawings are usually made 
to a scale much less than the actual size. of the required work, 
and always represent the completed or finished machine or one 
of its parts. 

Drawings are made for the machine shop to guide the machinist 
in cutting, turning, planing, and fitting the parts given, so as to 
produce in the castings the shapes, sizes, and general requirements 
of the articles to be constructed. Hence there is less hability for 
mistakes after the castings reach the machinist, as he has before 
him not only the drawing with its accurate dimensions to work 



62 



PATTERN MAKING 



from, but also the castings for the machine or its parts, from all 
of which the construction and uses of these several parts can easily 
be understood. 

On the other hand, the pattern maker, with the aid of the 
same drawing, must imagine the casting before him, and must 
build something in wood which will produce that casting in metal. 
This pattern, in some cases, will be a duplicate of the required 
casting, but more often it has only a general resemblance to it, 
with core prints attached, and is external only, ^^■ith nothing to 
show the internal openings^ chambers, and winding passages that 
must be provided for by coring. The core boxes, in which the 
cores are to be formed, are not shown in the drawings furnished to 
the pattern maker, but must be provided by him in correct shapes 
and sizes, in addition to the pattern itself with its added core prints. 

In building a pattern the workman, as before stated, must 
allow for shrinkage. He must also allow for draft and for finish. 



Stock Allowances 

Shrinkage. The shrinkage of cast iron when cooling in the 
molds is, as has before been stated, about | inch to each foot, and 
the manner of obtaining the exact 
? , > -' tZy:^ sizes for different parts of the pat- 

tern has been explained in the sec- 
tion on ^Measuring Tools. For brass 
or bronze castings a greater allowance 
must be made, averaging ^ inch to 
each 12 inches. Shrinkage rules for 
brass ajlowing -^ inch to the foot 
can be obtained, and must be used 
for all patterns made from brass. 

Draft. After shrinkage, the 
second point of importance in a 
well-made pattern is draft. By the term draft is meant the bevel 
or taper made on all vertical parts of the pattern so that it can 
easily be hfted from the sand without injury to the mold. This 
is best illustrated as in Fig. 132, in which it will be seen that if the 
diameter of a pattern at a were to be the same as that at 6, the latter 
point would drag over the whole length of the sand until it reached 




Allowances in Molding 
Gland 



PATTERN MAKING 



63 



the former point. As the sand is held together only very lightly, 
this dragging would be Hkely to dislodge some of the particles 
and make it necessary to mend the mold. In order to avoid this, 
the diameter at a is made slightly greater than at 6, so that the 
body of the gland is tapering, and the moment it is started out 
the whole surface from a to 6 is clear of the sand and can be removed 
without injury thereto. This difference in the diameters at a 
and h is called the draft of a pattern. 

Variation, The amount of draft depends upon the length 
of the part that is to be drawn out of the sand. The allowance 
for draft, which varies with the pattern, is often greater or less on 
different parts of the same pattern. For example, the draft on the 
outside of the pattern of a pulley rim, 24 inches in diameter and 




Fig. 133. Draft Template 

(T inches face, should be \ inch to the foot, while on the inside of the 
rim and on the hub of the pulley it should be in the ratio of f inch 
to the foot. The reason for this difference is that the face of the 
rim is often turned and finished straight, and for that reason the 
least possible amount of draft which will allow of the pattern being 
removed from the sand should be used, while on the inside of the 
rim a greater amount of draft is necessary if the inside of the pulley 
mold is to be coped to the center of the arms. This mass of sand 
hanging from the cope is lifted or drawn from the pattern with the 
cope flask, and will require a greater draft to be sure of obtaining 
a perfect lift. 

Draft Template. To obtain any required amount of draft 
correctly, a draft template, kept with other tools and templates. 



64 PATTERN MAKING 

will be found convenient and useful, saving much time when changing 
from one ratio of draft or bevel to another. It is made as follows: 

Take any straight-grained board 14 inches to 16 inches long 
and 12| inches wide, as sho^^^l in Fig. 133. Having jointed the 
edge a perfectly straight, draw the line b perpendicular to the edge 
and 12 inches long, using a steel square and a sharp-pointed knife — 
not a scratch awl or a lead pencil. On the edge a carefully measure 
J inch on each side of b; and at the upper extremity, with the same 
care, measure f inch on each side of b; connect the last two points 
thus found with the first two on the edge a by a sharp knife line, 
and the result will be a right and a left slanting line, each havmg, 
with reference to the perpendicular, a slant of | inch to a foot. 
These Hues should each be marked ''| inch", as shown in the drawing. 

Now draw a second perpendicular c, at a distance of 1^ inches 
or 2 inches from the first. On the edge of the board a again care- 
fully mark off | inch on each side; at the other extreme mark off 
•fjs inch on each side of c, and again connect the latter points Tvith 
the former. The result will be a taper of 3^ inch to a foot. Again 
repeat the process, making the taper J inch, and lastly | inch, to a 
foot. Mark the pairs of right- and left-hand tapers, '*J inch", 
"ys inch", **| inch", ''| inch", respectively, as shown. These 
lines having been obtained permanently, the width of the board 
may be cut down from 12| inches to 6 inches, as shown by the 
dotted line A B, and the board then shellacked. 

To use this template, place the bevel against the edge a of the 
board, and carefully adjust the blade to the |-inch, -^-inch, or 
other draft, right or left, as may be required. It will readily be seen 
that whatever may be the width of^ the surface to which the bevel 
is applied, the taper or draft will be the exact proportion of the 
given amount for each 12 inches. 

Finish. In pattern making, the term finish refers to the 
additional thickness besides shrinkage and draft, which must be 
given the pattern in places where the casting is to be planed, turned, 
chipped and filed, or fitted, in the machine shop. The amount 
that is to be so added is, to a certain extent, though not wholly, 
independent of the size of the piece. For small articles whose 
longest dimension does not exceed 3 or 4 feet, an addition of | inch 
to the surface to be finished is usually sufficient. For larger dimen- 



PATTERN MAKING 



65 



sions it may be necessary to add as much as | inch or | inch, but 
very rarely more than this. In making this allowance it is also 
well to bear in mind the tendency of the casting to warp in cooling. 
Where the thickness of the metal varies to any great extent, there 
is a greater liability to warp than if a uniform thickness prevails 




Fig. 134. Pattern for Plain Bar 

throughout the wholes Hence, in such cases, a greater allowance 
must be made for the finishing. 

On small pieces, and where the molding is carefully done, it 
may be possible to make as small an allowance as ye i°ch, but 
as a general rule sufiicient metal should be'put upon the casting to 
allow the cutting tool of the finishing machine to cut well below 
the surface so that it shall not become dulled by the sand and the 
hard scale on the outside. 

Example of Allowance. A pattern for the plain cast-iron bar 
illustrated in Fig. 134 will afford a good example of the allowance 

necessary for finish and for draft. 

\* ^^-^^4' ^ This bar is to be finished all over, 

the finished sizes being 36 inches 





Fig. 135. Allowances for Finish 
and Draft 



Fig. 136. Position for Molding without 
Added Draft 



long, 1 inch wide, and 1 inch thick. A slender bar of this length is 
liable to warp or bend when cooling in the mold, and for this 
reason the bar should have an allowance of at least | inch all over 
for finish, thus requiring a pattern 36| inches long, 1| inches wide, 



66 PATTERN MAKING 

and IJ inches thick — actual dimensions. Moreover, to enable the 
molder to remove the pattern from the sand without injury to the 
mold, we must add on two of the opposite sides a draft of about 
I inch to the foot, making a cross-section through the pattern 
of the shape and dimensions shown in Fig. 135. 

\Mien accuracy is required in testing bars — 1 by 1 by 36 inches, 
and seldom finished — they are often molded partly in the cope and 
partly in the drag, as shown in Fig. 136, the parting being on the 
hne ab. In this position the inclination of the sides of the pattern 
in the mold is so great that no draft is required, the pattern being 
simply a square bar of wood of dimensions 1 by 1 by 36 inches, 
measured with the shrinkage rule. 



PATTERN MAKING 

PART II 



CONSTRUCTION OF PATTERNS 

SIMPLE TYPES 

Conditions of Procedure. Whenever the building of a pattern 
is consigned to the pattern maker, a detailed sketch or drawing of 
the completed casting should be furnished; also information regard- 
ing the number of castings that are required. It may be a repair 
part, or experimental work, and only one casting required, and, if 
so, it would often be economy to make the pattern as cheaply as 
possible, even if the expense of molding is slightly increased. Or it 
rftay be for a standard casting, for which it is expected to use the 
pattern for years, and in this case special study should be given the 
manner of construction, to prevent the distortion and general 
breakdown of the pattern, due to its shrinking, warping, and abuse. 

INFLUENCE OF MOLDING METHOD 
One=Piece Patterns 

Green=Sand Coring. The simplest patterns are those which are 
made in one piece, and which require no coring, although the castings 
themselves may be hollow. Deciding the method of molding indi- 
cates the way in which the pattern is to be removed from the sand, 
and where the parting line of the pattern, if there is one, should be. 
As an example of a simple pattern of one piece made without a 
dry-sand core, the stuffing-box gland shown in Fig. 132, Part I, is a 
good illustration. It is readily seen that, if the pattern of such a 
gland were to be imbedded in the sand as shown, there is no Reason 
why it could not be lifted out without disturbing any of the sur- 
rounding or the internal sand. The drawing represents the pattern 
with draft and finish added, the finished gland being shown by the 
dotted lines. 



68 PATTERN MAKING 

Core* Any part of a mold which projects far enough into the 
cavity to form a hole or recess in the casting is called a core, whether 
it is formed by the pattern or is placed in the mold after the pattern 
is drawai. In the case where the core is made by ramming the 
molding sand — called green sand — into a recess in the pattern, it 
would be known as a green-sand core, as shown in Fig. 132, Part I. 

The use of the green-sand core is limited to cores of compara- 
tively short length and large diameter. To illustrate: A pattera 
designed for a green-sand core 2 inches long by ^ inch in diameter 
would be very difficult to draw without lifting or breaking the core, 
and also the inrushing molten metal w^ould wash away some of the 
core — for a green-sand core of these proportions cannot be rammed 
very hard and permit drawing the pattern, although a pattern with 
a core of this kind 1^ inches in diameter and 2 inches long could be 
easily drawn and it would have sufficient strength to withstand the 
pouring process. A green-sand core of comparatively small diam- 
eter, should have more draft than those of larger diameter which 
should have a draft of | inch per foot, this being the usual draft 
allowance for the outside of patterns. 

Typical Construction. In order to give a better understanding 
of the methods employed in pattern making, the object itself will be 
illustrated, and when it is to be finished, the finished dimensions 
only will be given. If the object is not to be finished, the sizes of 
the completed castings will be shown. These dimensions will, in 
^11 cases, be arbitrary, and may be changed at will, if for any reason 
alteration is necessary. The successive steps in the construction of 
the pattern are given in detail so that the student may fully under- 
stand the principles involved. 

Dry-Sand Cored Bushing, The first article for consideration is 
the brass bushing flanged at one end, illustrated in Fig. 137. This 
bushing is to be finished all over, and as the casting is small, ye inch 
will be sufficient for outside finish and the same for turning out the 
inside. On examining it with regard to molding, we find that if 
molded on end with the flange up and on the parting line of the 
flask it can be readily removed from the mold. In making the 
mold from this pattern, the cylindrical hole in the casting will be 
made by the use of the' dry-sand core as described in the section on 
Molding Practice in Part I. 



PATTERN MAKING 



69 



The draft in this instance should be | inch per foot. It is well 
to have standard dimensions for the core prints for reasons explained 
subsequently relative to standard core prints. The lower core print 
should have the same proportion of draft as the body of the pattern, 




l luiiiiiii ljijijj j i iiiliiis 



llillil i '^ 

i i! i iii!;:!! 



i 



iilMMIililliliUlHIIIlin 




Fig. 137. Finished Bronze Bushing with 
Flange at Cue End 



Fig. 138. Plan and Elevation of Pattern 
for Bronze Bushing 



but the upper core print is given the excessive draft of ^ inch to its 
length so that the cope can be easily liited off and returned again 
over the tapering end of the dry-sand core without injury to the 
mold; the parting of drag and cope being on the line a 6 at the 
flanged end of the bushing. 



70 



PATTERN MAKING 




. 139 Clued Stock with 
Heart and Bark Sides 
Reversed 



Having the finished sizes given, as in Fig. 137, and having decided 
on the amounts of draft and finish, the pattern will be as represented 
by Fig. 13S. In the case of this simple pat- 
tern, as in all others, a full-size drawing, or 
sketch, giving all the dimensions or the pat- 
tern, should be made by the pattern maker 
before beginning work on the pattern; this 
is good practice, and, if carried out, many 
mistakes and much loss of time will be 
avoided. 

Shaping Pattern. This pattern may 
be turned from a solid block of wood, but 
if durability is desired, the block should be glued up from 4 pieces 
of |-inch pine, care being taken to reverse the annular rings or yearly 
grovNlh of the wood, as shown in Fig. 139. Place the block in the 
lathe and with the gouge turn to a cylin- 
drical form of slightly greater diameter 
than the largest diameter of *he pattern, 
say 3-i^ inches. 

Finishing to diameter should be done 
by the use of scraping tools. For the 
body of the pattern, a firmer chisel 1 
inch Tside is a good tool, but the cutting 
edge must be ground and siiarpened 
slightly rounding, as described for plane 
irons; otherwise the corners of the tool 
are liable to catch and form grooves on 
the surface. For turning the ends to size, 
use the right- and left-hand skew chisels, 
not with a scraping cut, but holding the 
chisel with its edge nearest the point 
resting on the tool rest. 

Forming Core Box. The core box 
for this pattern is shown in Figs. 140 
and 148, which are representative of the 
half box used for all symmetrical cores. 
In this box, two semicircular or half cores are made, which, after 
being baked in the core oven, are pasted together, first having a 




Fig. 1 40. Core Box for Bronze 
Bushing of Fig. 13S 



PATTERN MAKING 



71 




Fig. 141. Core-Box Stock with Construction Lines 



small groove scratched along the center of the flat side of each half, 
to form a vent for the gases generated during the pouring. A small 
V-notch, as seen in Fig. 148, should be cut at the center of each 
end of the half-core box 
to assist in making this 
vent« 

Gouging Cylindrical 
Section, For the part a 
of the core box, a block 
of slightly greater length 
(^ inch or 1 inch) is first 
planed up to the exact size. A center line, shown at h, Fig. 141, is 
drawn with the marking gage parallel to one of the edges, and also 
extends across each end of the block. From this center line, at a dis- 
tance of iS inch on each side, 
the lines d and e are also 
drawn. Then, with a second 
block or strip of wood placed 
against the face of the block 
and flush with the end, the 
two pieces are clamped to- 
gether in the bench vise, as 
shown in Fig. 142. Now, with the dividers adjusted to if inch, 
describe on each end of the block the semicircle which connects the 
lines d and e on the ends of the block. This wood may be removed 
rapidly w^ith a gouge and mallet, 
smoothed with a round plane of 
proper size and curve, and finished 
by sandpaper rolled on a cylindrical 

s block having a diameter -^ i^^^h less 
than the width of the required box. 
As the work progresses, the ac- 
curacy of the curve is tested by 
means of a try-square or other 90-degree angle, as shown in 
Fig. 143. 

Right- Angle Methods. Another method frequently used for 
small boxes, is to work out the center of the curve with a rabbet 
plane, forming a right-angled opening, as shown in Fig. 144, the 




Fig. 142. 



Layout of Box before Gouging Cylindrical 
Section 




Fig. 143. Right-Angle Test of Circle 



72 



PATTERN MAKING 




remaining wood being removed with the round pUme and finished 
with the cyhnder and sandpaper as before. 

If the machine-saw table can be tilted, as in Fig. 97, Part I, 
a cut similar to that in the previous method can be made, Fig. 145. 

Turning Tapered Section, The ta- 
pered end of the box c, Fig. 140, is turned 
from a block of wood, screwed to the 
faceplate of the lathe^ as shown in Fig. 
146. After the hole is turned to the re- 
Fig. 144. Rabbet-Planed Opening quired |-inch depth, and to the required 
l|-inch size on the outside, and to If inches at the bottom, it is 
removed from the faceplate and the piece c is cut out, as shown by 
the dotted lines in Fig. 146. This piece c is glued and nailed to the 
end of a. The two ends of the box are now given a slight draft — 
I inch in 12 inches — to allow the half core to leave the box easily. 
The end strips d and d, Fig. 140, are then nailed on, and the box is 

/fzpping Fence TV^ complete. 

Approved Process. 
While taking up the con- 
struction of this core box for 
a cylindrical dry-sand core, 
it will be well to consider 
other methods of proced- 
ure, and herein lies one of 
the engineering features of 
the trade — to be able to 
discern which method is 
best adapted to the require- 
ments. 

Another method which 
has some advantages is that 
shown in Figs. 147 and 148. Select stock with a width of about 1 
inch greater than the diameter of the required core, with the depth 
about half this width, and the length slightly longer than the total 
length of the pattern, including the core prints h. Dress this stock 
to a parallel thickness and width. Scribe a center line with the 
marking gage on one side, and cut one piece d, Fig. 148, for the 
cylindrical part of the core — the length b to include the length of 




Fig. 145. Skeleton View of Machine Saw with 
Table Tilted to 45 Degrees 



PATTERN MAKING 



73 




Fig 14G. Cope End of Core Box Mounted on Faceplate 
lor Turmng Tapered Section at c. Fig. 140 



the nowel core print — and cut another piece e to the length c of 
the cope core print. 

The uaste in the semicylindrical hole in d is to be removed as 
follows: Make two machine-saw cuts, as at i, Y\g. 147, about ,-% ^^ch 
deep, and locate them so 
as to have the outside 
edge equal the diameter 
of the required core a. 
Cut out the remaining 
stock as shown, so as to 
be able to break out the 
stock left standing. Re- 
move the remaining 
stock with the core-box 
plane, as described in 
the section on Hand Cut- 
ting Tools in Part I. 

Scribe semicircles on piece e, Fig. 148, for the large and small 
ends, to correspond to the dimension of the cope core print. If there 
is a J-inch band saw, tilt the table and saw to these lines, or remove 
the stock with a gouge. ' In either case, finish smooth on a small 
sand roll, unless the hole in 
the e section is very small, 
when it should be finished by 
hand. Size the ends of d and 
e, and glue together. As 
soon as the glue is set enough 
to allow handling, nail the 
ends / on, and cut the 
grooves g with the machine 
saw and glue a spline of soft 
wood in each. IVIachine-saw 
a slight amount of stock from 
the side and ends to clean the outside. A narrow chamfer should be 
planed on the outside corners, but no other work done to the out- 
side. The advantage of the spline is, that if the core box is to be 
altered, by saw^ing out the spline the box is easily broken apart, and 
the spline replaced after the changes are made. 




^ig. 147. Method of Removing Waste Stock 



74 



PATTERN MAKING 




Finishing. Shellacking. Having completed the pattern and its 
core box, the surface of the wood must be covered with some material 
which will render it hard, smooth, and impervious to the moisture in 
the sand, and at the same time make it easier to be withdrawn from 
the mold. Pure grain-alcohol shellac varnish is the best for this 
purpose. All cheap substitutes, such as wood-alcohol shellac, or 

copal varnishes should 
.^ ><:^^^^^^^^^^ be avoided ; they become 
flaky and scale off, and 
do not stand the expos- 
ure and moisture. Pat- 
tern makers generally 
make their own shellac 
varnish, bu>dng only the 
best quality of shellac 
gum, and using 95 per 
cent proof alcohol. The 
proportions are 3 pounds 
of gum to 1 gallon of 
alcohol. The gum is put 
in a wide-mouthed bottle, or earthen jar, and the alcohol poured 
over it; and, if well stirred three or four times during the day, this 
will — if the alcohol is of the best — give a smooth clear orange-colored 
varnish, ready for use. 

A good grade of white grain-alcohol shellac may be made from 
bleached gum., or can be bought from the dealers, but it dries more 
slowly and does not produce so hard a. sur- 
face as the orange shellac. Orange or 
white shellac varnish should never be kept 
in a metallic can or cup, as the oxidation 
of the metal will discolor the varnish. 
As the alcohol in shellac varnish evap- 
orates very rapidly, the brush should be kept in a vessel which is 
closed and air tight. A short bottle having a mouth wide enough 
to admit the brush is best for this purpose. A 1-inch flat double- 
thickness fitch hairbrush is good for general w^ork. Do not use a 
cork, but turn a wooden cap for the bottle, such as is shown in 
Fig. 149, and of which the shoulder at a may be ^^ inch to J inch 



Fig. 148. Completed Core Box 




149. Wood Cover ff>r 
Shellac Pot 



PATTERN MAKING 75 

long, but must be at least \ inch less in diameter than the inside of 
the mouth of the bottle. Otherwise the shellac will cement it to the 
glass so that it cannot be removed. Its only object is to keep the 
cap nearly central on the bottle. The handle of the brush must \)e 
tightly fitted into a hole through the center of the cap and fastened 
with a screw or brad, allowing the brush to reach within ^ inch of 
the bottom of the bottle. Keep the bottle one-third to one-half full 
of shellac, and use the brush with the cap on the handle. The shel- 
lac will make a tight joint between the bottle and the cap, and, if 
the proper amount of shellac is kept in the bottle, the brush will 
always remain soft. 

For small patterns, such as the bushing described, the small 
quantity of shellac needed can be used directly from the bottle. 
For large work, however, an earthenware cup or mug should be 
usdd, but the shellac left over should always be returned to the 
vessel in which it is kept. 

Sandpapering. Having given a perfectly smooth surface to the 
pattern and core box by the use of very fine sandpaper — No. — 
apply the first coat of shellac. This first coat will raise the grain 
and roughen the surface of the wood, which, after the shellac is 
perfectly dry, must be sandpapered a second time until smooth. 
Now apply a second coat. Should there still be roughness, a second 
sandpapering will be necessary. At least three coats of shellac 
should be used. If there is much end wood exposed on any of 
the surfaces of the pattern, a fourth coat may be necessary on 
these parts. 

Coloring. . As regards the color in which patterns are finished, 
there are different rules in different shops. The general rule, how- 
ever, is to leave all patterns for brass or bronze in the natural color 
of the wood, and to shellac the core prints red. If the pattern is 
intended for molding cast iron, the body of the pattern is made 
black and the core prints red. The parts of the core box in which 
the core is to be formed are also colored red and the outside of the 
core box black. The black color is produced by mixing lampblack 
with the shellac varnish, and the red color by mixing vermilion — 
Chinese is the best — with the shellac. The vermilion is heavy and 
will settle, hence it must be stirred or well shaken before using. The 
best method is to first use two coats of the natural colored shellac — : 



76 PATTERN MAKING 

orange or white — on all surfaces of the pattern, core prints, and core 
box, then apply the black or red for the last coat only. 

As the pattern already described is for a brass bushing, the 
body should be left the natural color of the pine, and the core prints 
on the pattern and the inside of the core box colored red. The out- 
side of the core box may be left the natural color or made black, as 
preferred. The outside of the core box, having no part in the forma- 
tion of the core, is not necessarily so well and smoothly finished as 
the inside. 

Final-Finishing. All nail holes or any defects in the wood 
should be filled with beeswax applied with the warm blade of a knife, 
or narrow chisel, warmed by holding in hot water. The beeswax 
should always be used after the first coat of shellac has been apphed, 
as it will then hold better. The sandpapering of the pattern, after 
the first coat, will smooth the wax and bring it even v/ith the surface 
of the wood. The time required for a coat of shellac to dry is from 
8 to 12 hours, depending upon how heavily it may have been applied, 
even though to the touch the surface may seem dry in 1 or 2 hours. 
K a hard durable surface is required on the pattern, 12 or better, 
24 hours must be given between each coat. The roughness will then 
sandpaper off as a dry powder without gumming the sandpaper, and 
leave a hard smooth surface for the succeeding coat of shellac. 

Split Patterns 

G)nditions. The second casting to which attention is called, 
is the brass bearing represented in Fig. 150, which is to be finished 
all over. On examining the drawing, first with regard to removing 
the pattern from the sand, we find that it must be molded on its side, 
and, that the molder may not lose the time required in cutting away 
the sand, as in Figs. 112 and 113, Pattern jMaking, Part I, the 
pattern must be parted or made in two halves. For finish on 
this small pattern ys inch will be sufficient, and draft will be required 
only on the ends of the pattern and on the ends of the core prints, 
which, in this case, should be not less than 1 inch long. This is 
necessary because the core-print molds must sustain the weight of 
the dry-sand core. 

iVlethod of Making. The pattern for this casting is repre- 
sented by Fig. 151, in which it is seen that, unlike Fig. 138, the body 



PATTERN MAKING 



77 



and core prints are perfectly straight, a slight draft — yg i^^ch in 12 
inches — being given to the ends only of the pattern and to-those of 
the core prints. A slight curve of yg-inch radius should also be made 
at the intersection of the body of the pattern and the inside of the 
flange at a a. The wood in being prepared for this pattern should 
be cut 2^ inches longer than the fin- 
ished pattern. The dimensions of the 
two halves would each be If by 3| 
by 8f inches. 

Having fitted the two insides ac- 
curately together, and dressed one 





. 150 Finished Bronze Bearing 
I'^langed at Both Ends 



Fig. 151. Pattern for Bushing, 
Fig. 150 



edge of each straight and at right angles to its face side, with the 
marking gage draw a center line on each, not only on the face but 
also across each of the two ends. Fig. 152. Place about J inch of 
the pointed end of a l|-inch wire nail on the center line, as shown in 
Fig. 152, and, striking it with a hammer, make an indentation at 
each end of both pieces of stock to form the location of the head- 



78 



PATTERN MAKING 




Prepanng Stock for Split Lathe Work 



stock and tailstock lathe centers. Glue | inch of the joint at each 
end, and clamp the stock together, being careful to keep the ends 
and the edges of the stock flush with each other. At the ends 
insert two metal corrugated fasteners, as shown in Fig. 153, placing 

them near the center of the 

end, but not so as to come 

ifmr^r^j^ ^ .^^^ in contact with the lathe 

centers. Drive a nail into 
the center hole in each end 
to force out the glue, for, 
if the glue* should harden, 
it would be impossible to 
center the stock in the 
lathe. 

Doiveling. The dowel-pin holes should be drilled before the 
stock is turned to a cylinder so as to ha\e them stand perpendicular 
to the joint. The location of the dowel pins should indicate w hich 
w ay the parts go together. If it is attempted to so locate the dowel 
pins that the parts can be assembled either way, it is very likely that 

they will not assemble accu- 
rately both ways — and when 
the nowel part of the pattern 
is in the mold it is not so easy 
to tell which w;ay is correct — 
so, unless the core prints are 
quite small, locate one dowel 
pin in the core print and the 
other in the body of the pat- 
tern, as shown in Fig. 154 
They could also be located to 
one side of the center line, if it 
is not desirable to put them in the core print. The dowel pins 
should be placed as far apart as possible to prevent side slip of 
the pattern when the dowel pins and holes have become worn 
Mark on one side of the stock the form of the pattern to show 
the location, and drill |-inch holes through the upper half of the 
stock and to a depth of about J inch into the lower half. The 
dowel pjiis need not be inserted until after turning. Glue a pin in 



End of Prxnt 




Fig 153. Split Stork Ready for Turning 



PATTERN MAKING 



79 



the holes drilled just deep enough to have the surface of the pattern 
turn smoothly. These pins should be made of the same stock as 
thiat used for the pattern. The dowel pins should always be inserted 
in the hole having a bottom, so that the pin cannot be driven below 




Fig. 154. Split Bushing Pattern Ready to Take from Lathe 

the proper height, and should always be placed in the cope part of 
the pattern, as in Fig. 151. 

Care Required, When centering the stock in the lathe, great 
care must be taken that the spur on the centers enters the small hole 
left in the ends of the stock exactly on the parting line of the pattern. 
Fig. 154 shows the pattern as ready to be taken from the lathe. 
Saw off the waste stock, 

'SI 



^of^ 



^ 



Pa/-t of Cope Bat tern -^-^^ 



Fig. 155. 



trim the ends true with a 
chisel, and sandpaper 
smooth. Shape the hard- 
wood dowels to the proper 
form, Fig. 155, and, after 
gluing them in place, clean 
off any excess glue. These 
dowel pins will always bring 
the parts into accurate 
alignment when used by 

the molder in the foundry. Before removing the turned pattern 
from the lathe, it should be smoothed and finished with sand- 
paper, but care must be taken not to allow the sandpaper to come 
in contact with the sharp corners and angles of the pattern, or 
they will be rounded off and the work ruined. For pine, only the 
finest paper — No. J and No. — should be used on lathe work, and 
the paper must not be held in one position on the revolving work but 
must be kept moving laterally, that is, from side to side, to avoid 



Diagram Showing Proper Proportions 
of a Dowel Pin 



'80 



PATTERN MAKING 



cutting depressions in the surface. WTien the scraping tools are 

kept sharp so that they cut freely and without pressure, a light 

touch of sandpaper only is required. 

Construction for Durability. In the construction of this pattern, 

it may be made of two blocks of If -inch stock as described, but the 

tendency of the two halves will be to 
become rounding on the parting line, 
as shown by the dotted lines cd and 





\ 


/ 

/ 




\ 
\ 


L^_ 




-^ 




' — 


•-~. 


\ 
\ 
\ 


_^ 


1 

1 
/ 

/ 

^ a 





Fig 156. Diagram Showing Tendency 
of Pattern Stock to Warp 



Fig. 157 Method of Glxiing Stock to Prevent 
Trouble Shown in Fig. 156 



ej, Fig. 156. This is caused by the removal of considerable wood 
in the process of turning, at the angles aaaa, thus exposing fresh 
surfaces which are farther removed from the original surfaces of the 
plank than the surfaces -on the line of parting. The exposure of 
these deep inside fibers of the wood will cause a shrinkage of the 
pores and draw the pattern more or less, according to the position 




Fig. 158. Core Box for Pattern, Fig. 151 

of the annular growths, and also to the more or less thorough sea- 
soning of the wood, in the direction indicated. 

If the pattern is intended for temporary use only, it may be 
constructed as above; but if durability and permanence of shape are 
required, the two blocks should each be glued up out of thinner 
stock, with the annular gro\vi:hs carefully reversed, as shown in 
Fig. 157. This is done not only because thin plank is more evenly 
and better seasoned, but because in gluing, the tendency of the 



PATTERN MAKING 81 

pieces to warp or spring is counteracted each by the other, and, in 
addition, the gluing of several thin pieces together stiffens and makes 
the resulting piece .much firmer and stronger than a large block or 
piece of the same size obtained without gluing. 

Core box. The core for this pattern being straight from end to 
end, and cylindrical, only a half-core box is required, as shown in 
Fig. 158. After being laid off and worked out in the same manner 
as described for the core box, Figs. 140 and 141, cut the ends of a 
with draft of I inch in 12 inches, and glue and nail on the ends c and 
Cj which may be f inch to J inch in thickness. 

Finishing. Shellac, and finish as described for the pattern in 
Fig. 138, giving first two coats of orange or white shellac, and for 
the last coat on the core prints of the pattern and the inside a of the 
core box use the red, the body of the pattern being left natural color 
— with three coats — and the outside of the core box either natural 
or black. 

FASTENING PROCESS 

Gluing. As the use of glue enters largely into the construction 
of all patterns, some instruction as to its selection and the manner of 
using is necessary. When building up patterns, the connections 
should in all cases be made by gluing. 

Use of Nails, Nails should never be used except when they 
can be so placed as to be entirely removed from all danger of contact 
with the tools used in turning and shaping the pattern, and when 
so employed should be used in conjunction with glue. The only 
advantage in their use is the hastening of the work, because they 
take the place of hand screws or clamps while the glue is drying. 
The use of nails, however, is always unsatisfactory, for when the 
point is passing through the upper piece, small thin slivers are broken 
from the under surface, which have a tendency to separate the two 
surfaces instead of exerting the required pressure as when hand 
screws are used. 

Kinds of Glue, For pattern work select only the very best 
quality of cabinetmakers' glue, or better still, the best quality of 
white glue. This white glue can always be had in two forms: 
(1) clear; and (2) opaque. The first is the glue without the addition 
cf any foreign substance. The second looks much whiter than the 



82 PATTERN MAKING 

first, because of the addition of whiting, or other mineral, to the 
glue. This addition does not in any way lessen the adhesive quali- 
ties of the glue; on the other hand, it sets more readily and dries more 
quickh', but for this very reason it is harder to use on large surfaces, 
as the first brushing on one part of the w^ork will begin to set before 
the entire surface can be covered. As this objection does not apply 
to small or moderate-sized work, however, the opaque white glue is 
to be preferred in such eases. 

Preparation, Good glue will keep in a dry room of any tempera- 
ture for an indefinite length of time, but when cooked in the gluepot 
it deteriorates very rapidly. Each successive reheating and boiling 
lessens its adhesive qualities, hence it should always be used fresh, 
or nearly so. A greater quantity of glue than is likely to be used in 
two or three da}'s should not be cooked at one time. 

The cooking and preparing must be done in the regular gluepot, 
made for the purpose, and sold in all hardw^are stores. No rule can 
be given for the relative quantities of glue and water to be used. 
Some glues, especially the cheaper grades, require much less w^ater 
than the better and finer qualities. As a general rule, however, pack 
the glue firmly in the pot and add sufficient cold water to cover it. 
Fill the outside kettle with cold w^ater and boil until thoroughly 
cooked, so that it will nm smo<ith and clear from the brush or paddle. 
It should run freely without returning and gathering in bimches or 
clots at the end of the paddle, but must not be so thin as to be weak 
and watery. 

If the glue is too thick, no amount of pressure will bring the 
tw^o glued surfaces in, close contact, and if too thin there is danger 
that the joint will not hold. Always use cold water for cooking 
and dissolving fresh glue. Hot or boiling water will make the glue 
stringy and will require a much longer time to cook to an even and 
smooth consistency. Great care should also be taken to keep the 
outside kettle, which surrounds the gluepot proper, full of water. 
If allowed to boil dry the glue in the inner pot will be scorched or 
burned, and will then be entirely useless. It must then be thrown 
out, the pot w^ashed or boiled out clean, and fresh glue again cooked. 
The hot water in the outside kettle should in all cases be used for 
thinning the glue to the required consistency. Cold w^ater chills 
the glue and necessitates reheating. , 



PATTERN MAKING 83 

Application. In cold weather the precaution must be taken, 
unless the room is warm and entirely free from drafts, to heat the 
pieces of wood before applying the glue, else the latter may be chilled 
and fail to set. The time required for well-made joints to dry so 
that the hand screws can be removed is from 4 to 6 hours. 

Sometimes a difficulty will arise in the case of large surfaces 
on thin material. When the glue is applied it moistens and expands 
the surface upon which it is placed, causing the edges to curl up 
and pull away from the adjoining piece which has a tendency to 
move in the opposite direction. In ^ich cases never moisten the 
back of the thin pieces with water from the outside kettle, as is 
sometimes directed, but, working quickly, spread the glue rapidly, 
and then place between two thick stiff pieces of board, previously 
dressed true, prepared and heated for the purpose. Use as many 
hand screws as can be conveniently placed on the work, and allow 
it to remain in these clamps until all moisture from the glue is 
absorbed by the two outside heated boards. Twenty-four, or 
better 48, hours should be given to this process, if possible. 

All such gluing of thin pieces should in every case be done first 
and allowed to dry while the other parts of the pattern are being 
constructed. Under no circumstances use water on any surface of 
seasoned wood. The reseasoning or drying out of such water will 
invariably distort, curl, and warp the pieces so treated, after being 
glued together. Even the water contained in the glue is objection- 
able, while unavoidable, and can be most satisfactorily removed only 
as directed above. 

In all cases where end wood is to be glued, or where the grain 
of the wood runs diagonally to the plane of the joint so as to present 
the open end wood pores for the glue, this end wood, or partially 
end wood joints, should be first sized with thin glue — glue about 
half the thickness of that used for gluing — and allowed to dry. 
This will raise the grain and roughen the surface of the joint, which, 
when dry, must be lightly and carefully scraped off with a sharp 
chisel, when it will be found that the open pores of the wood are 
filled with dried glue. The joint may now be glued, and the glue 
will hold as in ordinary jointing. 

Clamping. Use of Hand Screws. The hand screws, illustrated 
in Fig. 79, Part I, Pattern Making, enter so largely into all gluing 



84 PATTERN 3IAKIXG 

for pattern work that some description of their construction and 
the manner of using is necessary here. The four parts of each hand 
screw consist of two jaws and two spindles. ^Yhen using, the jaws 
must in every case be kept paralleh This is done by the adjust- 
ment of the middle or central spindle. The clamping is in all cases 
done by the outside or end spindle, the middle or adjusting spindle 
serving as a fulcrum for the jaws, and the leverage and pressure 
being obtained by the end spindle. 

To open and close the hand screws for larger or smaller work, 
do not screw or unscrew one spindle at a time. Instead, grip the 
handle of the middle spindle in the left hand, and the handle of the 
end spindle in the right hand. Hold the hand screw at arms length 
and whirl it from or toward you as may be needed for closing or 
opening the jaws. In this way the spindles will each be kept in its 
proper relative position, and the jaws will, at all distances, remain 
parallel. 

Pressure Regulation, ^Mien clamping broad surfaces, care must 
be taken to see that the pressure of the jaws on the work being glued 
is the same at the points and at the back part of the applied portion 
of the jaws. This can be easily changed at will, by slightly loosen- 
ing or tightening the middle spindle, which, as before stated, is the 
adjusting spindle and fulcrum, and not used for clamping. After 
adjusting the jaws parallel and to even pressure on all their length 
as applied to the work, screw up and tighten the end spindle to 
the utmost pressure which the jaws 'vv'ill bear, and again examine the 
clamp and the work to see if the jaws are parallel and the pressure 
even. If not, loosen the end spindle and readjust the middle spindle 
by opening or closing as the case may require. 

BUILT-UP PATTERNS 
Sheave Pulley 

Green=Sand Ring Coring. For practical reasons, the first 
method of molding — for green-sand core, or, in this case, ring — 
the 6-inch sheave pulley shown in Fig. 159 would ordinarily not be 
used. The expense of molding would more than offset the alterna- 
tive extra expense caused by making a dr^'-sand core for the groove 
in the outer edge of the sheave. However, consideration of this 
method is offered at this time solely for the study of the manner of 



PATTERN MAKING 



building the pattern, as it will be found practical to use this process 
in making numerous other patterns. The study of the molding 
process is also of value. The molding of this pattern is as explained 
in connection with the use of the green-sand ring, under Molding 
Practice, Pattern Making, 
Part I. ^^^ 

Making Master Pattern. 
The wood pattern for this 
casting, molded as described, 
is comparatively frail, so a 
working pattern should be 
made of some aluminum 
alloy in order that the 
weight wdll not interfere 
with the molding process. 
The metal pattern should 
be lathe finished all over; 
consequently the wood pat- 
tern shall include stock for this finish. Allow yg- inch on each sur- 
face for this finish, besides the allowance for the aluminum shrink- 
age which will be about J inch per foot. These must be added to 
the shrinkage allowed for the metal used in the final castings; if 
the final castings are to be of iron, and the metal pattern made 




Fig. 159. Small Sheave Pulley 




Fig IGO Section of T'attern for Sheave 

of cast aluminum, the shrink allowance should be based on. a 
shrinkage of | inch per foot. The wood pattern is called the masier 
'pattern. 

A cross-section through the finished pattern for this casting is 
shown in Fig. 160. The groove is a semicircle 1 inch wide, and the 
rim containing the groove is connected with the hub by a solid web 
\ inch in thickness and having four or six holes, eaph 1 inch in diam- 
eter, this web taking the place of arms. If there is to be no finish on 



86 



PATTERN MAKING 



the sheave, as is usual, the only allowance to be made on the pattern, 
which must be parted, will be for shrinkage and for draft. 

Segmental Construction, In all patterns of this kind, the web is 
first glued up in sectors, Fig. 161, six, eight, or more in number, 
according to the size of the sheave. The sectors are fitted by hand 
or on the trimmer, the ends are glue sized, and 
when the sizing is dry the joints are carefully 
scraped smooth and the whole glued together. 
After drying for 4 or 5 hours, it is sawed to a 
circle of ^ inch greater diameter than the fin- 
ished pattern, and the block for the hub is 
glued over the center. Six segments to form 
the outer rim are glued around on the outer 
edge, care being taken to break joints, as 
shown in Fig. 162. If the groove is to be 
large, the six segments should be of half the 
thickness only, and a second set of segments of like thickness 
glued over the first, breaking joints not only with the first set, 
but also with sectors of the web. In other words, in all glued-up 
rims, no two joints should be directly over each other. All joints 




Fig, 161. Segmental Con. 

struction of Web for 

Sheave Pattern 





Fig 162. Web with Rim Glued On 



Fig. 163. Construction Mews of Sheave 
Pattern 



must be so broken and so distributed as to give the greatest possible 
strength to the rim. 

In the present case, our pattern is so small that it is only neces- 
sary to use a thin board J inch in thickness for each half of the web. 
After sawing to 6§ inches in diameter — J inch for turning — a block 
J inch in thickness is glued on the center of each half to form the 



PATTERN MAKING 



87 




Fig. 164. Stock Mounted on 
Faceplate 



hub, and six annular segments 1 j inches wide and ^ inch in thickness 

are glued around on the outer surface of each to form. the rim and 

groove, as shown at a and h, Fig. 163. Care must be taken to place 

the segments so that the grain of the web wdll be crossed by two of 

the segments, as shown in the drawings. 

On the second half, 6, of the pattern, a 

thin circular block \ inch in thickness is 

glued on the inside opposite to the hub 

block, to form the |-inch projection which 

will keep the two halves of the pattern in 

alignment, as shown in the cross-sectional 

drawing in Fig. IGO. Having glued up 

th^ stock as described, and as shown in 

Fig. 163, the outside must be planed to a 

level surface, or so that the six segments 

forming the rim and the center hub block 

will be in the same plane. 

The half pattern a is now screwed 
on the screw chuck of the lathe, as illus- 
trated in Fig. 164, and the inside, or the parting face c is turned 
perfectly straight and true. The edge is turned down to 6 inches 
in diameter, and the quartered circle shown by the dotted lines 
in Fig. 159 is carefully shaped. A template, as at d, Fig. 164^ 
will assist greatly at this stage of the work. A recess is turned at 
the center and in the face of a, Fig. 160, \\ inches in diameter and 
\ inch deep, to receive the corresponding projection on the half pat- 
tern h which is to keep the 
two halves in alignment. 

The half pattern a is 
now removed from the screw 
chuck, and the second half 
h is screwed on and turned 
in the same manner except 
that the central projection is carefully turned to fit in the recess 
in a. Before removing h from the chuck, test by trying the 
second half a, and change h until a perfect fit is obtained between 
the two halves, not only in the central recess and projection, but 
also in the two curves wh^ch form the semicircular groove of the rim 




Fig, 105. Section Showing Joint of Sheave Tit tern 



PATTERN MAKING 




Fig. 166. Method of Mounting 

Sheave Pattern on Wood 

Faceplate 



A cross-section of the pattern at this stage of construction is shown 

in Fig. 165. 

A disk or chuck of wood 5^ inches in diameter is now screwed 

to the iron faceplate, or the screw chuck, and turned off true on 
the face, with a projection | inch high 
which will fit into the recess in the middle 

Jili /mi of the parting face of a. By this pro- 

^M II 1 jection the half pattern a is centered on 

/M — mm e the faceplate, and can be held in position 
by two or four short w^ood screw^s driven 
through the web into the wooden chuck, 
as shown in Fig. 106. Care must be 
taken to place the screws in such a posi- 
tion that the screw holes will be cut or 
bored out when making the four or six 
openings 1 inch in diameter in the fin- 
ished web of the pulley. The screws 
must be small and slender and the heads 
well countersunk out of reach of the turning tools. The face of the 
half pattern is now turned to Jihe required shape, the template 
shown at e^ Fig. 166, being used for the purpose. Having finished 

with fine sandpaper, remove 
the half pattern, and, turn- 
ing off the projection on the 
center of the wooden chuck 
and making a recess instead 
to receive the projection on 
hy proceed with this second 
half as with the first. 

The 1-inch holes in the 
w^eb are bored out with a 
1-mch center bit, which, 
when well sharpened, does 
not split or splinter the thin 
webs of the two halves of the pattern if care is taken to reverse the 
bore from the opposite side when the point of the center bit comes 
through. The holes should be given a slight draft, as shown in 
Fig. 160. 




Fig. 167. Sheave Pulley Pattern with Groove 
Made with Dry-Sand Core 



PATTERN MAKING 



89 



If the wood has been well seasoned, and the work carefully 
done, a perfect 6-inch sheave-pulley pattern will be obtained. The 
pattern for a sheave pulley has been explained because it embraces 
so many profitable points and conditions, not only in gluing and 




Radial Section 



Fig. 168. Core Box for Sheave Pulley 

building up, but especially in chucking and turning, all of which 
must be done with great care and accuracy. 

Dry=Sand Ring Coring. A more practical way to produce 
castings of a sheave wheel would be to construct a solid wood pat- 
tern with a core print, as shown in Fig. 167, and to turn a half-core 
box, as shown in Fig. 168. In fact, this dry-sand-core method would 
result in greater economy in the foundry, as the saving in time 
required to mold the pattern would not be offset by the expense of 
making the dry-sand core. 

When very large sheave pulleys having arms are to be made, 
such as are common for power transmission by rope or cable, the 
patterns are not halved 
but are made in one piece 
and the groove is cored 
around the rim, as illus- 
trated in Fig. 167, with 
a wide core print cc ex- 
tending entirely around the 
periphery of the pattern. 

Segment Core. A segmental core box is made for one-sixth or 
one-eighth the circumference of the wheel, as shown in Fig. 169, and 
here again only half of the core box for a full core is needed. When 
coring the rim as above, the core print must be made deep, at least 
2 to 3 times the depth of the groove, so that the core may rest firmly 



^^ 




J5— ' 



SecHon R-B 



Fig. 109. Core Box for Single-Groove Rope Sheave 



90 



PATTERN MAKING 



and remain in position without tilting while the metal is being 
poured into the mold. 

Hand Wheel 
Conditions. The 12-inch hand wheel, Fig. 170, with five arms 
and a round rim finished to 1^ inches in diameter, will also serve as a 
good illustration of pattern construction. On the rim of the pattern 
^ inch over all its surface must be allowed for finish, making the 
diameter of the rim of the pattern If inches and the outside diameter 
of the pattern 12J inches, while the inside diameter of the rim will be 
8J inches. 

To hold this work a wooden chuck— in this case a plain board 
12f inches in diameter, and | inch to 1| inches in thickness— is 

screwed to the iron face- 
plate of the lathe, and 
■ turned true on the face 
and on the edge to 12| 
inches in diameter. 

Spider Pattern. The 
arms in this case should 
be made | inch in thick- 
ness at the hub and J inch 
in thickness where they 
enter the rim of the 
wheel. The construction 
is as shown in Fi^. 171. Five pieces, each 6i inches long, 2| inches 
wide, and f inch in thickness, are necessary. 

Jointing Web, After being carefully fitted on the trimmer, a 
saw kerf ye irich deep is cut in each joint, a, Fig. 171, into which a 
thin tongue of wood is inserted and glued, the tongues serving as 
tenons to hold the arms together. After fitting, and before grooving 
with the saw kerf, the joints must be glue sized and, when dry, care- 
fully scraped smooth with a sharp chisel. The grain of the wood in 
the tongues must run at right angles to or crosswise of the joint to 
insure the greatest strength. 

Laying Out Arms, When glued together and dry, mark with 
dividers set to a radius of 6 J inches, from the center or intersection of 
the five pieces, and cut off the ends of the arms so that they will 
project clear through the rim. 




Fig. 170. Five-Arm Hand Wheel 



PATTERN MAKING 



91 



From the same center describe a circle 3J inches in diameter, 
forming the web of the arms; and from this 3|-inch circle, taper the 
arms to J inch in thickness at the ends, care being taken to plane 
the same amount from each side, and to dress the arms evenly so 
that they will revolve in the same plane. This being done, from 
the center describe arcs on the outer ends of the arms, with a radius 
of 4f inches (8f inches diameter, which is | inch less than the inside 
diameter of the rim), and divide the imaginary circle thus formed 
into five equal parts with the dividers. Draw radii from the points 





Fig. 171. Construction of Arm Pattern 



thus obtained to the center. These radii will be the central lines of 
the arms, as shown by the dotted lines in Fig. 171. 

On each side of the intersection of the radii and outer circle, 
measure | inch to the right and left, and on the circle denoting the 
circumference of the web, mark H on each side of the radii; connect 
the points thus obtained, and the result will be five arms If inches 
wide at the web and 1 inch wide at the rim, as shown in the drawing. 
The ends of the arms which enter the rim should be, in this case. 
If inches wide, and the sides are drawn parallel to the radius which 
marks the center of each arm. The curves which connect the arms 
at the hub must be drawn of such radius as to make the curve tan- 
gent to the circle forming the extremity of the web, and also tangent 
to the sides of the two connected arms, as shown at d. The small 
circles at the intersections of the arms with the rim must be tangent 



92 



PATTERN MAKING 



to the edge of the arm and to the 8|-inch circle which marks t6 inch 
less than the inside diameter of the rim, as shown at cc. 

Having laid out the arms as above, and as* outlined by the 
dotted lines in Fig. 171, saw them to shape and, before proceeding 

further T\ath the arms, build 
the rim of the pattern on the 
faceplate. 

Building Rim, Prepare 
stock ^ inch thick, and saw to 
a length slightly greater than 
the chord for five segments. 
Stack and nail three of these 
pieces together, and lay out 
one segment, as shown in 
Fig. 172, as follows: outside 
diameter to be 12§ inches; 
width of segment 2 inches; 
and the chord equaling the 
diameter multiplied by the 
sine of half of the included angle, for example, the included angle 
being 72 degrees, the sme of 36 degrees equals .5877, and 12.5 
times .5877 equals 7.35 inches, the length of the chord. Band saw 

these segments and use 

f/rjf Layer of Segments the top segment to lay 

out the other segments, 
marking them with a 
pencil. Glue a sheet 
of paper to the face- 
plate on the location of 
the rim of the pattern, 
and carefully fit and 
glue five of these seg- 
ments to the paper, 
fastening the segments 




Waste iStock 



■ Fig. 172. Stock Prepared for Band-Sawing 
Segments 




Woocf Face-Plate - 

Fig. 173. Partially Assembled Rim and Pattern 



at the same time with two 1-inch finish nails. The heads of 
these nails should be driven below the surface of the stock. Be 
sure that the segments are concentric w^ith the center of the 
faceplate. 



PATTERN MAKING 93' 

As soon as the glue is dry, turn the face and the outer and inner 
edges of segments true. Locate the partially completed arms on 
this ring and fasten temporarily with five small nails, Fig. 173. 
Remove from the lathe, fit and glue the five segments between th^ 
ends of the arms, clamping these segments with two hand screws 
each while the glue is drying. Remove the arms as soon as the 
segments are glued in place, to prevent them from being glued in. 
As soon as the glue has set firmly, remove the hand screws and turn 
the inside edge of these last segments to their proper diameter and 
form, using a small sheet-metal template of zinc to test the form 
while turning. This turns the rim between the arms. Glue the 
arms in place, and also the last layers of rim segments, using the 
hand screws as before. The upper half of the rim can now be turned, 
using the template. 

Before reversing, glue and nail five blocks of wood to the face- 
plate between the arms, pressing these firmly against the inner edge 
of the rim; these will serve to center the pattern afterward. The 
pattern can now be removed from the faceplate with a thin chisel 
and mallet. The paper will split and the nails will pull themselves 
either out of the pattern or the faceplate, and may be removed 
with a pair of pliers. Refasten the pattern on the faceplate by 
passing slim wood screws through the arms into the faceplate, or 
up through the faceplate into the rim. The five blocks glued to the 
faceplate will keep the work concentric. These screw holes can be 
filled with glued plugs when finishing the pattern. 

Shaping Spokes, Trimming the arms to an elliptical form, as 
shown in the cross-section at Figs. 174 and 175, can be carried on while 
waiting for the glue in the rim to dry. 





Construction Lines for Section of Fig. 175. Final Form of 

Arm of Pulley Arm between Rim 

and Hub 

The finished shape of the arm, at any point in its length, is found 
by drawing a cross-section of the arm at that point, as in Fig. 174. 
Divide the cross-section equally by the line ^5; meac^ureout f^ inch. 



94 



PATTERN MAKING 



as at aci and c/, and with dividers adjusted so as to be tangent to 
the sides of the cross-section of the arm, and to pass through ad 
and c/, draw the curves ahc and def. After working off the sides of 
the arms to these curves, the angles at a, c, d, and / are carefully 
rounded with sandpaper, care being taken not to lessen the width 
of the arm at any pomt. The result will be as shown in Fig. 175, 
which gives a strong firm edge to the arm, and one which will not 
break or splinter off while being rammed up in the sand. 

Forming Hubs. The hubs are to be turned from solid stock 
and with a draft or taper of f inch in 12 inches, and must have a 

curve of |-inch radius at the 
base where they imite with 
the arms. If the hubs and 
the diameter of the cored 
hole are not liable to be 
changed, the nowel hub 
should be fastened firmly to 
the arms, and should be 
chucked into the arms, as 
shown in Fig. 176. This pro- 
duces a fillet between hub 
and arms which is not liable 
to become loose. The fillets 
on both nowel and cope hubs 
should be tinned on, and the 
cope hub should be made 
loose so that it will lift with 
the cope mold. If the pattern is to be completed as cheaply as possi- 
ble, the hubs can be turned with a short 1-inch dowel, and fitted to a 
1-inch hole at the center of the arms. In this case the fillet can be 
left off the cope hub, as a fillet this way is very fragile and easily 
broken. The molder will form the fillet iu the green-sand mold. 
If the hubs are to be let into the arms, the recess in the arms can be 
chucked at the same time the rim is turned. 

After gluing on the nubs, smooth off all connected parts 
of rim, arms, and hub, and finish with three coats of shellac, 
sandpapering smooth between each coat as already described for 
other patterns. 




Fig. 176. Section through Center of Ann Hub and 

Core Prints. Nowel Hub Glued to Arms; 

Cope Hub Loose 



PATTERN MAKING 



'95 



Countershaft Pulley 

Construction for Special Size. The making of patterns for 
special pulleys enters largely into the work of many pattern shops. 
In these patterns the rims are built up of segments f inch to | inch 
in thickness. To illustrate this work fully, let us take up the suc- 
cessive steps in the construction of a countershaft pulley 20 inches in 
diameter and of 6-inch face, made to fit a shaft If inches in diameter. 
The pattern for such a pulley is shown in Fig. 177. 

Alloivances in Dimensions, The diameter of the web of the 
arms is 5 inches, and the diameter of the hub 3§ inches at each end 
and tapering up to 3| inches in diameter at the arms. 





Fig. 177. Sectional View of Pattern for 20-Inch Pulley 

If the rim is to be finished on the face and edges only, ^ inch 
must be allowed for facing, making the outside diameter of the 
pattern 20| inches; and the width of the face should be 6| inches. 
In addition to ^ inch for finish, the draft on the outside of the rim, 
from each edge to the center, should be in the ratio of | inch to 12 
inches, and on the inside of the rim the draft must be \ inch in 
12 inches. The thickness of the rim at its thinnest edge is | inch 
and, with outside and inside draft added, its thickness at the arms 
will be about | inch. The inside diameter of the rim at the arms 
will be 19| inches. 

Arms. This pulley should have six straight arms f inch in thick- 
ness at the hub and f inch in thickness at the rim. The width of 



96 



PATTERN MAKING 



the arms at the web should be If inches and at the rim 1^ inche?, 
exclusive of the connecting curves at web and rim. 

Jointing. Six pieces 10§ inches long, 2| inches ^^^de, and f 
inch in thickness, must be carefully fitted, as sho\\Ti in Fig. 178. 
After fitting, the connecting joints are glue sized, and, when dry, 
carefully scraped smooth with a sharp chisel, and a saw kerf j^ inch 
deep cut in each. The tongues used for tenons in these kerfs should 
be a little less than | inch long, the grain of the wood running always 
at right angles to the line of the joint to give the greatest strength 
to the tenons. 

The six pieces should be glued in two groups of three pieces 
each; and, when dry, these two groups can easily be refitted, if neces- 
sary, and glued. 

Laying Out The 
next step is to draw, 
from the center formed 
by the intersection of 
the six pieces, a circle 5 
inches in diameter, rep- 
resenting the web of the 
arms, and, near the ex- 
tremities of the pieces, 
the arcs of a circle 20| 
inches in diameter, rep- 
resenting Yb iiich greater 
diameter than the outside 
diameter of the rim at the 
location of the arms. Carefully divide these last arcs into 6 equal 
spaces with the dividers, bringing the points thus obtained as nearly 
to the middle of the six arms as possible; and from the six points 
thus spaced, draw radial lines connecting them with the center or 
intersection of the six arms. These radial lines, shown dotted in 
Fig. 178, are the center lines of each arm. 

Saw of! the ends of the arms on the above 20^-inch arcs, and 
from the center again draw on the six arm pieces a third circle, 
w^hose diameter should be at least | inch less than the inside diam- 
eter of the rim— in this case 19 inches.- On these arcs measure 
I inch on ^ach §ide of the center line, and on the <jircle representing 




Fig. 178. Layout of Arms for Fig. 177 



PATTERN MAKING 97 

the web measure J inch on each side.; connect these points from web 
to rim, and the arms will be If inches wide at web, and 1| inches 
at the rim» 

These lines are shown by the dotted lines in Fig. 178. The 
width of the ends of the arms passing through the rim should be 
about 2J inches, and the sides of the end sections should be drawn 
parallel with the center line of the arm, as shown for the hand-wheel 
arms in Fig. 171. The radius of the circle connecting the sides of 
the arms and the web must be such as to be tangent to the edges 
of the two connected arms, and also tangent to the circle marking 
the diameter of the web. 

The smaller curve connecting the two edges of each arm with 
the rim must be of such radius as to be tangent to the arm and to 
the lOf-inch arcs which mark the inside of the rim in the plane of 
the arms. All these lines are shown dotted in Fig. 178. 

Shaping, The arms are now ready for sawing to shape on the 
band or scroll saw, care being taken to saw just outside of the lines 
so that each arm may retain its full size and width. After sawing 
to shape, the edges must be dressed smooth and free from all irregu- 
larities of the sawing. 

Next, from the web circle, taper the arms to | inch in thickness 
at the extreme ends, care being taken to see that the taper of both 
sides of the arms is uniform from the web circle to the rim. 

The shape of the arms should be elliptical or nearly so, and a 
cross-section at any point in an arm may be obtained in the 
same manner as described for the hand wheel shown in Figs, 174 
and 175, and the methods used for shaping and finishing are 
the same. 

Rim, Construction, Use of Chuck. For building the rim, a 
wooden chuclc 20J inches in diameter will be necessary.' A board 
I inch in thickness and having a bar 8 inches wide and of the same 
thickness, well screwed to the back with wood screws, is all that is 
necessary for a pulley of this size. To the 8-inch bar, the iron face- 
plate of the lathe is screwed, and the whole turned off true in the 
lathe, especially the face of the chuck to which the first layer of 
segments is to be glued. 

Strips of paper will be glued between the first layer of segments 
and the face of the faceplate so that the completed rim may be 



98 PATTERN MAKING 

easily removed — repeating the process used for similar work in 
making the 12-inch hand wheel. 

Process, Prepare stock f inch thick for rim segments, cutting 
the stock long enough to make 6 segments for each layer, and 11 
layers, making 66 segments. Stack the stock and band saw at least 
4 segments at one time. Have the layout and process carried out 
the same as suggested for the 12-inch hand wheel. 

The segments should have an outside diameter of 20| inches, 
and inside diameter of 19 inches, making a width of f inch, and a 
length Y& ii^ch longer than the outside radius. The grain of the 
stock should be parallel to the chord of the segment. 

The first layer is fitted and glued to the faceplate with paper 
between, and securely clamped with small hand screws through to 
each segment. Do not use any nail this time, as the rim is only 
Y^ inch thick at the edge next to the faceplate. When the glue is 
dry — one hour being sufficient^ — place the faceplate in the lathe and 
carefully turn off the face of the segments true, and also turn the 
inside edge of the segments to the proper diameter and draft. 

Before turning the face of the second layer of segments, glue to 
the faceplate — six pieces of stock |-inch thick — using no paper — so 
that they will bear firmly against the inner edge of the segments in 
the first layer, to prevent the work from becoming loose. Do not 
glue these blocks to the rim segments. No nails should be used in 
any work of this description. Fit and glue the second layer, and 
when the glue is sufficiently dry, turn the face and also the inside 
edge as before. Do not turn the outside edge of the segments at 
this time, but it is best to mark an oversize diameter with a pencil 
or the point of a chisel to keep the layers concentric. This layer, 
in turn, is turned off in the lathe, and the third layer is glued on, 
hand screws being used on each layer as on the first, and the joints 
of the segments so broken that no two will be directly opposite each 
other, all joints being carried to right or left of all preceding joints, 
thus securing the greatest possible strength to the rim. 

Having glued on a sufficient number of layers to build the rim 
up to the edge of the arms — five in this case — fasten the arms tem- 
porarily in their correct location, and glue the segments between 
the ends of the arms. Remove the arms— as noted while consider- 
ing the 12-inch hand wheel — and turn out the inside of the rim 



PATTERN MAKING 99 

to the finished diameter and draft, and smooth with sandpaper. 
Glue the arms back into place, first seeing that the fillets which 
have been used at the outer end of the arms are trimmed to fit the 
the inside of the rim. 

The next five layers of the rim are built on the same way, except 
that the inside edges need not be turned until all layers are in place. 
The outside of the rim should be turned straight, with its largest 
diameter next to the faceplate. This diameter should be 20 1 inches, 
and, as the outer edge of the rim is to be made 20 1 inches in diameter 
to allow facing, this gives ^V i^^ch for draft. 

The parting of the mold should be flush with one edge of the 
rim, and coped down to the center of the arms on the inside of the 
rim. This allows more than the usual amount of metal finish on 
one edge of the rim, but, if the face of the rim were crowned or 
drafted both W'ays from the center of the arms, a perfect lift would 
be difficult when the cope mold is lifted to get at the pattern. 

Use of Loose Hub. To permit a satisfactory lift, the cope hub 
should be made loose so that it will lift with the cope mold. In 
constructing any pattern it is best to so arrange its parts that change 
may be made in order to adapt the pattern to as many require- 
ments as possible. Even if this pulley is designed as a standard 
part of some equipment, there are times when it might be used for 
other purposes that would likely require a larger shaft, a longer, 
or an offset hub. To meet these conditions, make all hubs and core 
prints loose. 

The pulley being intended for a 1 f-Inch shaft, the core prints 
X and ?/, Fig. 177, should be ll inches in diameter, which will give 
I inch of metal for boring out to fit the shaft. The hubs should be 
turned from solid stock, having the grain run parallel to the length 
of the hub. Select stock 4 inches by 4 inches and saw two pieces 
2 1 inches long. Band saw to a circle 3| inches in diameter and bore 
a 1-inch hole through each at the center. Mount these pieces on 
an arbor; turn to a diameter of 3i- inches at one end, and a draft of 
about I inch per foot should be allowed on the outside diameter. 
The length of the hubs should be 2 J inches each. 

Fillet. No fillet should be turned on the large end of the hubs, 
as it is easily broken and it will be easier to lengthen the hub by 
the addition of a thin piece of stock, should o^^a.^iou demand, if the 



100 PATTERN MAKING 

hub is made straight. The molder can produce the fillet by slicking 
the corner of the mold with a fillet tool. 

Core Prints. Core-print usage is discussed in the next section, 
in the paragraph on ^'Standard Core Prints" 

Standard Pulleys 

Method of 'G>nstruction. It is the same with the pulley pattern 
as with most other patterns — the number of castings required and 
the complexity of the demands determine the method of molding. 
Several methods of molding a pulley, and the dependent pattern, 
are considered. 

Iron Rim Pattern, When pulleys of standard sizes for line 
shafting are manufactured in quantities, a skeleton pattern con- 
sisting of hub, arms, and an independent iron rim is used. This iron 
rim is of moderate width but may be used for obtaining any width 
of face desired. 

Rim Master Pattern. Shrinkage Allowance, Where a wood 
pattern for the iron rim is to be made, the same care is necessary in 
the building up of the original wooden" pattern. It must be remem- 
bered that before the final casting is obtained, two shrinkages will 
take place; first, the shrinkage of the original casting from which the 
iron ring is turned, and then the shrinkage of the casting made from 
this pattern. In addition to this, there must be the allowance for 
turning the ring both inside and out and for the turning of the out- 
side pulley rim. 

Suppose the pattern \s to be made for a pulley 2 feet in diameter. 
The usual allowance for a single shrinkage is made by the shrinkage 
rule. In this case the allowance must be doubled. Thus, in the 
above pulley, the diameter of the wooden pattern becomes 24| + |- 
= 24 J inches, standard-rule measurements, or 244-J = 24| inches, 
shrinkage-rule measurements. As a very smooth surface free from 
holes is required,-^ mch in diameter, or \ inch all around must be 
allowed for outside finish on the iron ring, and \ inch for finish on 
the rim of the cast-iron pulley. 

The outside diameter of the original wooden pattern is 24i-f- 
J-l-| = 24f inches, with shrinkage rule. If the final thickness of 
the pulley rim is to be f inch, this, with the allowance of \ indi 
for turning out the inside of the iron ring, makes the inside diam- 



PATTERN MAKING 101 

eter of the wooden pattern 23 inches, and the thickness of the wooden 
rim tl inch, all shrinkage-rule measurements, 

Comtrudion, This wooden-rim pattern must be built up on a 
chuck, as described for the 20-inch by 6-inch pulley, the segments, 
six in number for each layer, fitted, glued, and clamped with three 
hand screws to each segment until a width of 6§ inches is reached. 

It is then turned to the above dimensions, without any draft, 
and sent to the foundry, where it may be used for obtaining an iron 
rim of any required width by first ramming the sand about the 
pattern, partly drawing it, and then ramming again to a new level. 

At least four pieces of stock about 3 inches long by 2 inches 
wide and | inch thick should be furnished the molder to bed in on 
the outside of the wooden-rim pattern at the moid parting, to permit 
casting lugs on the rim for clamping the casting to the faceplate 
while it is being finished to final dimensions, the casting being made 
wide enough to cut these lugs off when the lathe work is completed. 

The casting thus obtained is then turncMl to the dimensions 
called for by an ordinary pattern; that is to say, the shrinkage-rule 
measurements would leave it 231 inches in diameter on the inside 
and 24| inches on the outside, permitting a final finishing of the 
outside of the rim of the pulley to a diameter of 24 inches. When 
this is done, two |-inch holes should be drilled near one edge of the 
rim and diametrically opposite each other, into which hooks may be 
inserted for drawing the pattern. This rim should also be turned 
straight and without any draft. 

Arms. The arms are usually made with a wooden pattern, 
which has a dowel-pin hole on each side at the center for attaching 
the hubs that are loose, the object being to change their length and 
diameter to suit the width of the rim and the diameter of the sliaft 
upon which the pulley is likely to be placed. 

Shape, The arms of all pulleys should be straight, because 
of the greater strength given to the pulley as a whole, the driving 
and resisting power bem'g at least one-third greater than in a 
pulley of the same dimensions having curved arms. Curved and 
shaped arms of all kinds are now used only for ornamental pur- 
poses and for very light work. 

Size, The arms should be six in number, except for very small 
pulleys, when five, and even four, are often used. The dimensions 



102 



PATTERN MAKING 



of the arms vary greatly, depending on the purpose foe which the 
pulley is to be used, and the weight of the machinery to be driven. 
For the beginner, the following formula is safe to follow: 

\7iX8 

in which — all dimensions being taken in inches — 

b = the breadth of the arm at the outer end 
c? = the outside diameter of the pulley 
w = the width of the rim 
?i = the number of arms 

Thus, for a pulley 24 inches in diameter, with a rim 6-inches wide and 
fitted with 5 arms, the formula becomes 



.=;/: 



5X8 
= 1.53 inches, or say 1| inches 

The width of the arm should be one-fourth greater at the hub 
than at the rim. The thickness at the hub and rim should be one- 
half the width, and the section should be elliptical. The arm just 
calculated then becomes 

IJ inches wide at rim 

I inch thick at rim 

1| inches wide at hub 

1 inch thick at hub 

As a rule, all of the dimensions of the 
pulley should be furnished the pattern 
maker by the designer. 

Lifting Plate. Use. In molding pat- 
terns made as above, the molder will 
require a lifting plate. The lifting plate 
is anchored to the top of the cope block 
flask and will lift the center of the mold 
without any liability of its dropping. 

Pattern, The patterns for this lifting 
plate can be made as follows: From a 
piece of stock f inch thick, band saw six 




Fig. 180. Lifting Plate Arm 



PATTERN MAKING 



103 



pieces, as shown in Fig. 179, making them about | inch smaller all 
around than the space between the two adjoining arms and the inside 
of the rim. Chamfer one edge all around so as to leave the vertical 
edge about J inch thick. Band saw six pieces from Ig-inch stock 




Fig. ISl. Assembled Lifting Plate for Six-Arm Pulley 

to the proportions shown in Fig. 180, and reduce the thickness at 
one end so as to form a draft. These pieces are drawn from the 
mold endwise, and the casting appears as shown in Fig. 181. Three 
circular pieces of stock Ij inches in diameter by 1 inch thick are 
furnished to form bosses, which are tapped for a |-inch or f-inch rod. 

Hubs. An ordmary rule is to make the outside diameter of the 
hub twice the diameter of the shaft. The two half hubs — one on 
each side of the arms — are usually loose and are held central by a 
single dowel pin. Their 
diameters are adapted to the 
size of the shaft upon which 
the pulley is to run, and the 
length is proportioned to the 
width of the rim as well as 
its diameter. The length of 
the hub should be about 
two-thirds the width of the 
rim, except in the cases of 
tight and loose pulleys, where 
the hub should be a trifle 
longer than the width of the rim, and it may then project about 
I inch on the sides in contact, and J inch on the outside. 

Rapping Plate. Use, When a pattern is imbedded in the sand, 
the latter is closely compressed all about it, and slightly adheres. 



Ctrsk. for mod 
screws or thrded 
formackscrews 




Draw Iron 



'Screw 



Draw Plate 

Fig. 182. Rapping and Draw Plate 



104 



PATTERN MAKING 



The molder is therefore in the habit of rapping the pattern gentl:* 
In order to loosen it in the sand before attempting to draw it. li 
the pattern is not provided ^vith a metal plate, the molder will drive 
the sharp point of a lifter into the wood and strike it alternately on 
opposite sides and at the same time use it to lift the pattern from the 
sand. This mars the pattern and will in 
time ruin it. 

The rapping plate shown in Fig. 182 is 
a piece of thin metal i to ^ inch thick, 
inserted so that it is flush with the parting 
face of the pattern and is held by wood 
screws with countersunk heads. These plates 
are drilled and tapped for a |-inch screw^ and 
should be the same for all patterns in the 
foundry so that one set of rods can be used 
interchangeably. The method of using is to 
screw the rod into the plate and rap it gently 
to and fro untilthe pattern has been loosened, 
when it may be lifted. 

The Acme key rapping plates, Fig. 183, 
are quickly attached to the pattern, the mor- 
tise being bored out with a bit. 

Placing. For small patterns, one rap- 
ping plate will be sufficient and this should 
be so placed that the hole for the lifting rod 
comes directly over the center of gravity of 
the piece. This prevents tilting of the pat- 
tern as it is lifted from the sand. However, 
if there is a portion of the pattern away to one side of the center of 
gravity, which by its nature is liable to resist drawing more than the 
other side, the rapping plate should be located away from the center 
of gravity toward this side of the pattern so that in drawing the lift 
will be neajly over the resultant center of resistance. For medium- 
sized patterns, two rapping plates should be provided so that the 
pattern can be raised from two opposite si-des. For still larger 
patterns three or four rapping plates are used, the object being to 
give such perfect control when drawing that there can be no tearing 
away of the sand. 




. 1S3. Rapping Plate and 
Draw Key 



PATTERN MAKING 



105 



Standard Core Prints. Economy in Use, AVhile standard 
dimensions of the cylindrical core prints are not universally used, 
many large corporations operating pattern shops and foundries 
have adopted a standard, and the economy of this practice should 
recommend it to all. Most foundries will keep on hand cylindrical 
dry-sand cores, whether the cores are made in wood or in metal core 
boxes or with the core machine. 

The value of the fixed taper and length to the cope core print 
is most apparent. This form can then be made at one end of the 
core box, and the machine-made cores can be ground to a fixed 
angle by having a guide table fitted to the emer> -wheel stand. A 
foundry equipped in this manner can alwa> s fit a pair of ])rints to the 
pattern and be sure that the cope end of the vertically set cures will 




■ ^Light Draft 

Fig. 184. Proportions of Standard Core Print 

fit the print mold. It v\ill -also save the pattern maker the expense 
of turning a pair of prints every time their use is required. A pattern 
shop, having a dozen pattern makers employed, will get a dozen 
different forms to the cylindrical core prints if no standard is fol- 
lowed, and much time will be used in the foundry filing cores to fit. 

Stock Sizes. If you know uhere the pattern is to be sent, better 
find out if the foundry has a standard for their stock cylindrical 
cores, and build your core prints to conform to it. 

There need be no standard length for the prints of a horizon- 
tally set core, for m this case the print should be long enough to give 
a s<^nting suffi('i<'nt to hdld the core from either settling or rising. 
The upuard strain of a cc^rc during pouring will be greater than the 
downuard strain diK* to its own weight 

Dry-sand cores are usually kept in stock from 1-inch up, by 
eighths, viz., Uinch, IJ-inch, li^inch, etc. All core prints used on 



106 



PATTERN MAKING 



patterns considered here will use prints dimensioned according to 
Fig. 184, unless they require a change in size due to extreme length 
and weight of the core, or to some special process of molding. 

Large Cored Pulley 

Molding Method, For the larger sizes of cast pulleys, including 
spur gears, rope sheaves, and balance pulleys, the wooden-arm and 
jnetal-rim patterns are impractical. In Fig. 185 are shown the 
dimensions of a single six-arm solid pulley which is molded by means 
of dry-sand cores and sweeping. The patterns for the double-arm, 




Fig. 185. Dimensions of Cored-Arm Pulley 

clamped between the arms, and clamped through the arms, are 
adaptations of the same process. 

Arm Core. First prepare an arm core box, Fig. ISO, which 
shows the core box with the near side removed so as to exhibit the 
hub and arm pattern in place. This box should be made of IJ-inch 
stock, and 3| inches deep by 10 inches wide inside; one end will be 
fitted to form a 60-degree angle, while the other end will be left 
open. jNIake the inside length about 48 inches, as this core box can 
be used for larger diameter pulleys. Have the core box well screwed 
together, cleated on the bottom, finished smooth, and shelhicked on 
the inside. 



PATTERN MAKING 



107 



Fig. 187 shows a section through the center of hub a, arm b, 
and inside rim pattern c, these three parts being made separate, so 
that by slight alterations they can be used for other diameters. 
The hub a is made of three pieces of stock, the lower being the 




Fig. 186. Core Box for Arm 

thickness of on^-half of the arm. The grain of this stock should be 
parallel to the length of the core box. Lay out from the center line 
the 60-de^ee angle and form of the arm at the center of the pulley, 
as shown in Fig. 1S7. The next two pieces of stock, a' and a", 
ohould have the grain at right angles to the length of the core box; 
the thickness of a' to be f inch, out of which is carved the fillet. 
These two pieces are to be fitted into the core box, and the arcs from 
the outside of the hub scribed from the center on the core box. 
The outside of a" may be smoothed with a spokeshave and sand- 
paper before the three pieces are nailed — not glued — together, but 






E 




Fig. 1S7. ConalnicuoD Diagram for Ari 

the fillet on a had best be carved after the assembly. Trim section 
a at cZ to make the round beading between the arms, and trim a at/ 
to a half ellipse. 

The rim end of the arm pattern c and its parts c' and c" are 
constructed by the same process, fitting the pieces of stock into the 



108 



PATTERN MAKING 



core box and scribing the arcs for the inside of c' and c" , The inside 
of c" should be finished smooth, using a spokeshave or a circular 
plane, as described in Part I. Carve the fillet on c' after assembling. 




Fig. 188. Section of Hub Core Box 



The arm h is planed to the required form of half the arm. These 
three parts are shellacked in the same manner as described before, 
and are fastened into the core box with wood screws. Be sure that 
the arm is central in the core box. 




Fig. 189. Inoide Flange Core Box 

Hub=End Core, The pattern for the ends of the hub receive 
our next consideration. The arm core box was made Z\ inches 
deep, so there remain 4f inches of hub outside the arm core box on 
each side, allowing \ inch for metal finish on the ends of the hub, as 
indicated in Fig. 188, 



PATTERN MAKING 



109 



Glue l|-inch stock together, to make the hub 12^ inches in 
diameter by 5 inches long. Plane one end true, bore a l-irich hole 
at the center, and, after band sawing to a rough diameter, fasten 
to a faceplate having a Irinch pin at its center. Turn to the required 
diameter and length, allowing a slight draft to the outside. Bore a 
1-inch hole at the center. If the hub is not too large, it should be 
turned' on an arbor, and also if quite large the hub may be con- 




Fig. 190. Centering Spindle and Rim Strike 

structed of two circular heads, nailing and gluing narrow stock- 
lagging — to the periphery of these heads or ends, and turning the hub 
after the glue is dry, as noted above. 

The core prints in this case can be made of flat stock fitting a 
1-inch pin at center, and nowel 6 and cope core prints should be about 
2 inches thick. An addition c to the core prints, 3 inches in diameter 
and about \\ inches thick, should be fastened and turned with them. 
The upper end of this 3-inch piece shall be flush with the frame, 
forming the outmde of the core. If the foundry is equipped with 



110 



PATTERN MAKING 



iron pulley-rim patterns, one of these can be used, striking down to 
the top of the 3-inch print c if the edge of the rim pattern is too high. 
Flange Core. The length of the core box for the inside flange. 
Fig. 189, will be made to allow twelve half cores. Multiply the inside 
diameter of the rim, 70 inches, by the sine of half of the included 
angle, .2588, which will equal 18.11 inches for the longest length of 
the inside of the core box. The thickness of the stock used for the 



-Eye- Bolt 




' Fig. 191. Section of Cored-Arm Pulley Mold 

core box should be about J inch, and the other dimensions are given 
in Fig. 189. 

Two patterns for the flange will be made, one to be nailed in 
place in the core box, and one to be used to mold the upper inside 
flange. 

Strike. The strike a, Fig. 190, is made of two pieces of stock 
\\ inches thick by 5 inches wide, halved together. The finger 
board h strikes the beading between the arms, and the mner end is 
sawed to the sectional form shown in Fig. 187. The length of 
strike a wul be 2-lJ inches long, allowing for J inch for metal finish 
on each edge of the pulley face. 



PATTERN MAKING 111 

Molding Process. A brief description of the molding process 
will make the use of this equipment clear. 

Twelve half cores are made in the arm box, Fig. 186, and pasted 
together to make six dry-sand arm cores. 

In the hub box shown in Fig. 188 one core is made for the lower 
end of the hub mold, and one core with the core print b cut through 
to the top of the core to clear the sweep spindle. Twelve cores are 
made in the flange core box. 

A cheek flask is bedded in the ground a and the standard with 
spindle is also bedded in, as shown at b in Fig. 191. The bed is 
struck off and. the flange cores set concentric with the spindle. Block 
up under the lower hub core at c and under the arm cores at c' and 
c" to locate the arms at the center of the face. A brick wall is 
loosely laid up just outside the lower flange cores, to the height of 
face required. The center is then filled with green sand and rammed 
hard, the upper hub core being placed over the spindle. The brick 
wall is now torn do\vTi and the strike set in position, striking off the 
green sand, to the end of the arm cores. 

The cheek flask being put into position a'a', the mold is rammed 
in green sand outside of the lagging which is placed next to the inside 
mold to give the thickness to the rim. The cheek is removed and 
slicked. The upper flange is bedded in at d; the spindle is withdrawn 
and replaced v/ith the shaft -hole core; the cheek is replaced; flat 
covering cores are placed over the rim mold e; and the cope is 
rammed. The gates, sprues, risers, and pouring basins will not 
require any pattern labor. 

Some molders prefer to make the outside of the rim with dry- 
sand cores, and this is always the method employed for rope sheaves. 

FLAT=BACK PATTERNS 

Solid Engine Crank 

Construction. The heavy engine-crank pattern illustrated by 
Fig. 192 should be built of five layers of stock, gluing heart sides and 
bark sides of each piece together, as shown in Fig. 193. Dress the 
stock true on one side and edge for a working face and a working 
edge. Machine-plane the opposite side and edge parallel to these 
faces. Lay out the plan of the crank on one face and also a side 
elevation on one side of the stock. Square around the stock for the 



112 



PATTERN MAKING 



locatiun of the holes — 15-inch centers — and bore 1-inch holes on- 
both sides of the stock at these centers. Carefully band saw to line 





R^ 



Section B'B 



Fig. 192. Detail Drawings fur Heavy Engine Crank 

a, Fig. 193, and leave stock at h so as to keep the top of the stock 
parallel to the band-saw table when sawing the line c. This stock 

h may be removed with a 
chisel after all band-saw 
work is completed. Have 
the band-saw table tilted 
when sawing to line c so 
as to produce a slight 
draft — I inch in 12 inches 
— fo the sides of the pat- 
tern. 

Turn a nowel and cope 
core print 3| inches and 
also 2f inches in diameter, 
according to the standard 
adopted for core prints. 
The bosses e and / are to 
be made of flat stock \ inch thick. Prepare a wood faceplate with 
a 1-mch pin at its center. Having a 1-inch bole at the center of 




Fig. 193. Diagram of Pattern for Crank, Fig. 192 



PATTERN MAKING 



113 



the boss, fasten the bosses to the faceplate with four |-inch wire 
nails; now turn them to the diameters required by the drawing 
and bevel the edge about 30 degrees. Nail and glue on the 
bosses, being sure the holes are in line with the holes in the 
body of the pattern. 

The sectional view m Fig. 192 shows the form of the crank at 
mid-length, and the pattern should be finished to this form, using a 
template to test the accuracy of the round corners. The dowels 
of the nowel core print should fit tightly, but are not to be glued 
to the pattern unless it is known that the size of the cored hole will 
not be altered. The cope core prints should fit loosely, so that they 
can be removed while ramming the nowel mold. The mold parting 
will then occur on line pp, Fig. 193, and the parting will be coped 
down to the round cor- 
ners. Patterns like Fig. 

193 and Fig. 195 are 
known as flat backed; 
no part of the pattern 
except the cope core 
prints extends into the 
cope mold. 

Disk Crank 

Construction. Fig. 

194 illustrates a finished 
cast-iron disk crank for an engine of 12-inch stroke. Tliis crank 
is finished on the face, on the outer edge, and on the end of the 
hub. It is bored out SJ inches to fit on the engine shaft, and 2\ 
inches to receive the wrist pin. An addition of J inch must be 
allowed on the pattern for finish of the face, and the same on the 
end of the hub; yq inch will be sufficient to add for finish on the 
outer rim, making the diameter of the pattern 16f inches, and the 
thickness of the disk f inch. A sectional view of the pattern is 
shown in Fig. 195. 

Disk, The disk or web for this pattern is to be made of six 
sectors. Fig. 196. The finished thickness of the web will be f inch, 
and, allowing J inch for metal finish, the web of the pattern will be 
I inch thick. Each section after being fitted should have the edges 




Fig. 104. Disk Crank 



114 



PATTERN MAKING 



glue sized, and be grooved for a spline. The grain of the stock used 
in these splines should be at right angles to the joint, as mentioned 
in the consideration of the hand-wheel pattern, Fig. 171. Band 
saw this web to a diameter J inch greater than required for the 
completed pattern, bore a 1-inch hole through the web at the center, 

and fasten to a wood 
'" '^ ^ *• faceplate ha\qng a 1-inch 

pin at its center, with 
six IJ-inch wood screws, 
as shown in Fig. 196. 
Turn the rabbet in the 
web at d and chuck the 
center at e, as shown in 
Fig, 195. 
Rim, The first layer of segments for the rim or flange are to 
have the inner edge fitted into the rabbet, and are made wide enough 
to make the wood fillet c. The other layers of the flange will not be 
required to be as wide, but make all segments of the same thickness, 
which should be about f inch, six segments to the layer, and put the 
work into the lathe before gluing on a layer of segment, and turn 

the face of the preceding 




Fig. 195. Section of Pattern for Disk Crank 



I Holo 



Wood Screws 




Plate 

Web Stock for Disk Crank and Faceplate 



layer true and concentric 
w4th the center of the pat- 
tern. Fit the segments care- 
fully and use three hand 
screws to hold each seg- 
ment while the glue is dry- 
ing; A w^ait of about two 
hours should be allowed 

Fig. 196. Web Stock for Disk Crank and Faceplate ^etwecn gluiug akyCfof 

segments and turning; so take advantage of the noon hour, and 
overnight. 

Bosses. The work on the hub, wrist-pin boss, and counter- 
weight should be proceeding while building the stock for the web 
and flange. The hub shall be turned from a solid piece of stock or 
from glued stock if the dimensions of the hub are too great. The 
grain of the stock used in the hub and wrist-pin boss should be 
parallel to the length of the hub. 



PATTERN MAKING 115 

If positive that the diameter of the cored holes will not be 
changed, the nowel core prints may be turned as a part of the hub 
and boss. The cope core prints x and ?/, Fig. 195, shall be loose on 
the pattern so that when the nowel mold is rammed these core 
prints can be removed when the pattern is laid on its back on the 
mold board.. The core prints should be shellacked a different color 
from the body of the pattern. 

The fillet at the base of the hub should be turned from the hub 
stock, as shown in Fig. 195. The hub is to be turned before it is 
glued to the web; the fillet, however, should be turned after the hub 
is in place so as to be tangent to the face of the web. 

Counterweight. The counterweight b is next shaped from a 
single piece, or it may be glued up of 2 thicknesses of l|-inch stock. 
In sawing this block to shape, the band-saw table should be tilted 
so as to give it a draft of f inch in 12 inches. Give the inside of the 
rim, the hub, and the boss a, the same draft as the counterweight, 
but the outside of the rim should not have a draft of more than 
I inch in 12 inches. 

Fillet, When turning on the inside of the rim, a fillet or curve 
of |-inch radius, as shown at c, Fig. 195, must be made where the rim 
joins the disk. Around the counterweight block, and also around 
the wrist-pin boss, a |-inch leather fillet can be used. 

FILLETS 
Usage, The fillets spoken of in connection with Fig. 195 are 
used in all except the most simple patterns. They consist of a small 
quarter curve varying in size from |-inch radius upward, depending 
on the size of the pattern and the room they can be 
allowed to occupy. They should be placed in cor- 
ners so that there may be no sudden changes in the 
direction of the surface of the casting, which causes 
weakness, the fillets adding greatly to the strength 
of the casting. Round corners and fillets should be 
used wherever possible, as they make a cleaner 
mold, the metal flows into and through the mold easier, the metal 
is not so liable to wash away the sand at the corners, and the shrink- 
age strains of the cooling metal are not so liable to start cracks at 
the corners. 




116 PATTERN MAKING 

Types, Wood. These fillets are made in various ways, the 
wooden fillet, cut as in Fig. 197, being comnK)nly used foralllong 
straight angles, or for very flat curves to which it can be bent. 
On large patterns intended for one or two castings, the fillets are 
three-sided pieces of stock nailed into the corner, giving a chamfered 
corner to the mold. The molder slicks this corner if necessary. 

Wood fillets, where they can be built in, are more durable, and 
should be used on all patterns intended to be standard, as in Fig. 19S. 

Wax and Leather. For irregular angles and for short radius 
curves, beeswax was formerly used, but the modern leather fillet has 
almost entirely superseded beeswax and other material for this 
purpose. It is easily applied, shaping and adapting itself to any 
and all positions and angles. It can be bought in all sizes from | inch 
up, the sizes running by sixteenths. 

The method of applying it is to cut it to the necessary length 
and lay it on a board where the glue can be easily brushed over it. 
It is then laid in the angle and rubbed into position by means of a 
dowel rod, the end of which must be rounded. The dowel rod must 
be of such size as to impart the required curve to the soft pliable 
leather fillet. As soon as the fillet is rubbed into position, all surplus 
glue must immediately be wiped off before it sets. This is easily 
done with a small piece of waste or a rag dipped in the hot water 
of the outer gluepot and wrung out nearly dry, care being taken not 
to wet any part of tlie pattern more than can possibly be helped, 
after which it must at once be wiped dry. These leather fillets will 
be found more pliable and more easily placed and rubbed into posi- 
tion if the glue used is first allowed to cool slightly. Very hot glue 
stifTens and crinkles the leather, causing it to work hard. 

Puffy. For patterns intended for temporary use, fillets made 
of linseed oil putty are often used. While this t>'pe takes some 
days to become hard, it is very low in cost and can be used for pat- 
terns of this class to good advantage. 

ECONOMICAL CONSTRUCTION 

Coring to Obviate Machining 

Example of Faceplate. It is sometimes advisable to use cores 

even if it is quite possible to construct the pattern so that it would 

core Its own holes. This is the case where it is desired that the 



PATTERN MAKING 



117 



faces of the casting and the holes shall be smooth and as true as 
possible without expensive machine work. . The finished faceplate 
of an engine lathe, illustrated In Fig. 198, is a good example of such 
work. 

It will be readily seen that the pattern for this casting could 
be put in the sand and withdrawn from the mold, leaving the sand 
standing where the holes are located. The trouble that arises from 
this method is due to the fact that, when the metal is poured and 
allowed to flow about the fragile projections that are left to form the 
holes, the sand washes away, so that the holes in the casting are 




(b) (&; 

Fig. 198. Typical Metal Faceplate 

irregular and much smaller than those in the pattern. For these 
reasons the holes should be cored, as the core sand is firm and better 
able to resist the washing action of the flowing metal. 

Core Prints in Drag, Where a large flat surface is to be given 
a finish, it is desirable that the metal should be as clean and free 
from sand and blowholes as possible. As the iron has a greater 
specific gravity than the sand of the mold, all particles of sand that 
may be washed away and all gases generated, rise to the surface of 
the molten metal. Those imprisoned by the cooling of the iron form 
the dirt and blowholes that disfigure the completed casting. In a 
casting such as the faceplate under consideration, it is desirable 



118 



PATTERN MAKING 



that the face should be upon the lower side when the metal is 
poured as it is to be planed smooth and should be clean iron. For 
the sake of convenience in setting the cores, the prints are put u|X)n 
the face and make their impress in the sand of the drag. 

• Construction, The construction of the web, 
rim, and hub is to be very similar to that used 
in making the disk crank, Fig. 195. If the 





Fig. 199. Section 

of Pattern for 

Faceplate, 

Fig. 19S 



Fig. 200. Core Box for Faceplate Slot* 



diameter is more than two feet, the grain of stock used in the 
web should be parallel to tlie radius. Each sector as it is fitted 
should be screwed to the wood faceplate, leaving a space of jV inch 
between each to allow for the swelling and shrinking of the stock. 
The ribs are fitted and 
fastened in place after 
the lathe work is com- 




Fig. 20^. . Tee Pipe Fittiag 



Fig. 202. Sectioa of Tee 



pleted; one extra rib should be furnished the molder for mending 
up the mold. Leather fillets are to be used in the corners made by 



PATTERN MAKING 



119 




Fig. 203. Elevation of Completed Pattern for Fig. 201 



the ribs. Iron draw plates are to be fitted in both ends of the hub, 
at a. Fig. 199. The core box for the cores making the holes in thf 
web is shown ir Fig. 200. 

Molding. In molding, a threaded rod is passed through the 
cope mold, into the draw plate in the cope end of the hub. It is 
securely fastened above 
the cope flask, so that 
the pattern will be 
drawn irom the nowel 
with the cope. By rap- 
ping on this draw iron, 
the- pattern can be 
rapped so as to obtain 
a perfect draw from the 
nowel mold. After the 
cope mold has been 
turned over, the pattern 
is drawn as usual and any mending required to the mold is facilitated 
by the extra rib furnished. 

Examples of Simplified Work 

T=Pipe Connection. Many patterns which at first may seem to 
be quite formidable, will, after a little study; resolve themselves into a 
few very simple parts, nearly all the work for which may be done in 
the lathe. Of this the T-pipe 
connection shown in Fig. 201 
is a good illustration. A sec- 
tional view of the casting, 
threaded and having a pipe 
screwed into the right-hand 
end, is shown in Fig. 202. 

The completed pattern 
for this casting is illustrated 
in Fig. 203, with its core prints a, a, and a, and must be parted, 
as shown in Fig. 204. The entire pattern may be made at a single 
turning, as illustrated in Fig. 205. The preparation of the wood 
for this pattern is similar to that described for the pattern, Fig. 151, 
of the brass bearing. 




Fig. 204. 



Plan View of Completed Pattern 
for Tee 



120 



PATTERN MAKING 



End Fastening, Some device should always be used at the ends 
of stock glued in this manner to assist in making a firm joint. The 
metal corrugated fastener is best suited for most requirements. In 



LK 



1 1 


"1 


[/ 


d 

c: 


C7l 1 


f 




c: 


M>— J 


\J 


»w 




faslenens 

Fig. 205. PutiorD for Tec, Fig. 201, as Mountod in Laihe 

some cases a flat head wood screw can be inserted at each end, 
Fig. 205, and the form of the pattern may require a wooden screw to 




Fit;. 207. Steel Pinch Dog 



be inserted near the center of the work to prevent its springing open 
at the center, due to tlic centrifugal furces at high revolutions. 



^ 




h 


--r ^'==:--s=s^=;^-s^^^29^-5^ 



Fig. 20'^. Coro Box (or Tl-c 





Fig. 209. Elbow Pipe 
Fitiiiig 



Lathe Mounting. In mounting heavy split patterns in the 
lathe, a sjxicial metal dog should be provided, and one such as in 
Fig. 20G will be found to meet most requirements for this class of 



PATTERN MAKING 



121 



work. In using this dog, which is also the center on which the 
work revolves, cone lathe centers should be used, and a steel pin 
should be bolted to the lathe faceplate and inserted in a hole in the 
end of the stock to drive the work. Several holes can be counter- 





Fig. 210. Section of Double-Elbow Pattern 

sunk in these metal lathe dogs when parts of the pattern are to be 
turned on several centers. The metal pinch dog, Fig. 207, is not 
adapted for lathe work, as it is liable to fly out when the work 
revolves, endangering the operator. 

Jointing, When the turning is completed, it is only necessary 
to cut a V-shaped opening into the two halves of e, into which the 
part / is to be fitted and 
glued. When the glue has 
set and is sufiiciently dry, 
the joint may be further 
strengthened by nailing, or 
by inserting and screwing a 
thin metal connecting plate 
flush with the parting side 
of each half of the pattern. 
This, however, will be nec- 
essary only when patterns 
are large and heavy, or when 
unusual strength is required. 

Core Box, The core box for this pattern, as will be seen in 
Fig. 208, is the usual half box and is made by working out the box in 
one piece long enough to make the two parts a and 6. The two 
parts are united by cutting a V-shaped opening in the part a and 
fitting 6 into it in the same way as described for the pattern. The 




Fig. 211. Method of Turning. Up Elbows 



122 



PATTERN MAKING 



whole is then glued and screwed to the board c, and the two triangu- 
lar blocks d and d are glued in the angles to add strength to the 
completed box. In case the pattern is for a very small pipe, IJ 
inches or under, the part b may be abutted against the side of a, as 



W ^ ^S 



Fig. 212. Turued-Up Flanges and Core Prints 

shown by the dotted line, and the side of a at e cut away to the same 
curve as b, giving the same results as in the former method. 

Pipe Elbow. The pattern for the 2-inch elbow, Fig. 209, is 
another illustration of how such work may be simplified, and time 
saved, by doing the greater part of the work in the lathe. 

Double Pattern. As these elbows are usually cast in large 
numbers, the patterns should be made double, as shown in Fig. 210. 




Fig 213. Ck)n8truclion of Ci>re Box for Eibow Fining 

To construct the double pattern, a ring is first turned like Fig, 211, 
a cross-section of which is a semicircle, as shown in the lower right- 
hand corner of the drawing. This ring is cut into quarters, and the 
four pieces e, e, e, and e make the quarter turns for the two halves of 
the double pattern. 

The ends, including the core prints and connecting tenons, are 
turned in one piece, as shown in Fig. 212, the stock for which is 
prepared, with the inserted dowel pins all in .position in the same 
manner as described for the T-pattern, Fig. 205. The quarters e, e, 
e, and e. Fig. 211, are clamped together two and two, and the end^ 



PATTERN MAKING 



123 




Fig. 214. Part of Core 
Box as Turned 



carefully bored to receive the tenons which are then glued in posi- 
tion and further strengthened by a wooden screw. 

Core Box, In Fig. 213 the core box for this double pattern is 
shown, and, as will be seen, the most diffi- 
cult part of the work can be done in the 
lathe. Fig. 214 shows two pieces jointed 
and clamped together wliich must be 
screwed to the faceplate of the lathe and 
turned out to make the two corners c and 
c. The three straight parts d, d, and d are 
worked out in one long piece and after- 
ward cut to the required lengths, after which the five pieces are 
glued and screwed to the board a. The ends e and e are next put 
on and the required half-core box is complete. 

Supported Core. Another reason why the pattern for pipe 
elbows should be made double is that otherwise the core prints 
would require to be made of 
great length in order to balance, 
sustain, and keep the heavy core 
in position; the tendency being 
to sag in the middle, or float on 
the molten iron, and thus make 





Fig. 215. Return-Bend Pipe Fitting 



Fig. 216. Section of Pattern for Pipe Fitting 



the upper side of the casting too thin, all of which is avoided in 
the double pattern. 

Return Bend. A pattern for the return bend. Fig. 215, may be 
built up and constructed in the same manner as described for the 
elbow; the semicircular returns, not only for the pattern, but also 
for the core box, being turned in the lathe, together with the ends 
and core prints for the pattern. As there will be no middle support 



124 



PATTERN MAKING 



for the core in this case, the core prints must be made as shown in 
the half pattern, Fig. 216, of sufficient length to balance the. heavy 
semicircular core, and also to keep it in its true position in the mold. 
Screw Chuck, The small wood lathe chuck, a vertical section 
of which is shown in Fig. 217, will serve as a simple illustration of 




Fig. 217 Screw Center 
Lathe Chuck 



Fig. 21S. Appearance of Pattern of Lathe Chuck 



the long core print and balanced core. The casting must be counter- 
cored ; that is, the cored opening must be enlarged at the forward 
end, adding to the size and weight of that end of the core, which, as 
will be seen, has no support except that afforded by the extra length 
of the core at the opposite end. The pattern for this chuck is shown 




Fig. 219. Core Box for Lathe Chuck Pattern 

in Fig. 218, and the core print must have a length at least twice as 
great as the depth of the hole in the chuck. The core box is shown 
in Fig, 219. 

Deep Flanges. When pipes or cylinders are of moderate size, 
with deep flanges for bolting together, Fig. 220, the flanges for the 
pattern are turned out of a separate disk, as shown in Fig. 221, and 



PATTERN MAKING 



125 



firmly glued and nailed on over the core prints and against the ends 
of the main body of the pattern; the core print being made of sufh- 



n f 






^iS^;:^ 


^s 


^==^ 




s<r 




^^ 


m 


i s^^=4 




Fig. 220. Flange Fipe Patlera 



cient length to receive the flange. A recess is sometimes turned in 
the inside, end of the core print to receive the inner edge of the flange, 





Fig. 221. Construction of Flanges for 
Tipe Pattern 



Fig. 222. Diagram Showing Rece.13 for 
Flanges in Pipe Pattern 



as shown in the diagram, Fig. 222; it can easily be seen that when 
the flange is fitted therein, it adds greatly to the strength of the joint. 



Looje Flange 




Fig. 223. Interchangeable Flanges on Pipe Pattern 

Flanges are often fastened to the pipe pattern by screws only, 
so that flanges of different diameter can be attached, Fig. 223. 

<Sfoc/c. The flanges should be made by gluing up three pieces 
and crossing the grain of the pieces so that the grain of each will run 
at right angles to that of the adjacent one. In gluing pieces together 



120 



PATTERN MAKING 



for thin disks, three pieces should always be used. Two thin pieces 
glued together will always warp. 

A still better and stronger method of making large flanges is 
to cut out segments, five or six for each course, and fit and glue up 
on a chuck and faceplate in the same way as described for the hand- 
wheel rim, Fig. 173. Two or three courses are used for each flange, 
which, after being turned to the required size and form, is sawed 

in two with a very thin 
saw, and each half fitted 
into place on the pattern. 





Fig. 224. Method of Assembling Wood for Large 
Pipe Pattern 



Fig. 225. . Light Pattern Con- 
struction for Cylinder 



Large Cylindrical Work. The patterns for the larger pipes or 
columns are to be glued up, as shown in Yig. 224, and, for turning, 
the two halves are held together by means of lathe dogs such as 
shown in Fig. 206, The treatment of this glued up stock in the 
lathe, is the same as employed in turning the small pipe shown in 
Fig. 220. The method of constructing the core box for this or 
similar patterns is shown at h, Fig. 224. Tees, elbows, and 
other bends and connections, when large, are built up in a simi- 
lar way. 

Hollow Construction, For large cylinders, a much lighter and 
simpler method of constructing the pattern is shown in P'ig. 225. 
For each half of the pattern the two end disks and the middle semi- 
circular disk are connected together by a strong center bar, which 
is fitted, glued, and screwed into each, serving not only to strengthen 
the pattern, but also to hold the connecting dowel pins. When the 
two halves of the pattern are clamped together, it serves also as a 
secure means of centering in the lathe. 



PATTERN MAKING 127 

The staves forming the body of the cylinder are fitted and 
glued to each other, and screwed or nailed to the disks. After the 
cylinder has been turned, the core prints and flanges are built up 





Fig. 226. Slightly Heavier Con- Fig. 227. Typical Core-Box Con- 

struction for Cylinder Pattern struction 

and turned separately, and glued and screwed to the ends of the 
cylinder from the inside of the end disks. 

Fig. 226 illustrates still another and better method of building 
up the cylinder and core prints in one piece and completing the hole 
at a single turning. The core prints, as shown, are staved up firsts 




Fig. 228. Gated Pipe-Coupling Pattern 

and then the staves to form the body of the pattern are fitted, glued, 
and screwed, or nailed, over the ends of those which form the core 
prints. For long cylinders use one, two, or more middle semi- 
circular disks. 



128 



PATTERN MAKING 



A similar construction for the core box is shown in Fig. 227, 
and is to be preferred to all others, because, if laid out and built to 
the exact size, the labor required to reduce the staves to a perfect 
semicircle of the required radius is very little. 

Quantity Production. Patterns for such work as pipe fittings 
would come under the head of standard patterns, as usually these 
parts are required in large numbers. The present-day practice of 
molding patterns for the smaller sizes of pipe fittings is to either 
have a number of similar patterns gated, Fig. 228, or resort to 
plate molding and stripping-plate molding machines. Some present- 
day methods of machine-molding pipe fittings are considered in 
Part III, Pattern ^Making. 

INTRICATE CORING 
Globe Valve 
Globe Construction. The globe valve, shown in section in 
Fig. 229, is a good illustration of a pattern in which, while the out- 




Fig. 229. Section of Globe Valvi 



side may be very simple, the inside is intricate and requires con- 
siderable practice and skill to so construct the core boxes that the 
core can be withdrawn from them, and at the same time give uni- 
form thickness and strength to all parts of the shell and to the 
internal partitions. 



PATTERN MAKING 



129 



In Fig. 230 is shown a sectional \'iew of the body of the valve, 
and in Fig 231 an illustration of the completed pattern, from which 




/jLfc. Section HB 

Fig. 230. Section of Valve Body 



it will be seen that almost the entire work, with the exception of 
fitting, placing the dowel pins, and forming the two hexagonal ends, 




Fig. 231. Appearance of Pattern for Globe Valve 

is done in the lathe. The construction is shown in the sectional 
illustration of the half pattern, Fig. 232. The wood for the two 




Fig. 232. Sectional View of Pattern and Template for Globe Valve 

halves must be of sufficient length to allow for gluing at each end. 
In turning, the greatest care must be taken to center exactly on the 
parting line of the two halves. 



ISO PATTERN MAKING 

Use of Template, A carefully shaped template, such as is shown 
at a, Fig. 232, must be used in turning. This template may be made 
of a thin piece of wood, but for all purposes for which templates are 
required in pattern tiaaking, and their use is necessarily very great, 
sheet zinc is the best material. It is soft, and easily cut and filed, 
and does not dull the cutting tools so much as other metals. 

Before marking out the template, that the lines may be more 
readily seen, it should be cleaned with a piece of emery cloth and 
have a dark coating of the following solution. Dissolve an ounce 
of sulphate of copper in about 4 ounces of water and to this add 
1 teaspoonful of nitric acid. Treat the surface of the zinc with 
this solution, rubbing on mth a piece of waste. A thin coating of 
copper will thus be given to the zinc — or, similarly, to steel or iron. 
When applied to finished surfaces they should be rubbed dry, as 
iron or steel will be rusted. 

When the curves of the template will allow of sawing, the 
zinc template is easily shaped by placing a piece of zinc of the neces- 
sary size between two boards and nailing them together. The 
required shape having been drawn on the upper board, the whole 
may be sawed to the form required on the band saw or scroll saw, 
but preferably on the latter, with a fine-tooth narrow saw blade 
which will give a smoother edge to the zinc. If the boards are firm, 
the metal will ofter no resistance whatever to the saw, nor will the 
saw be perceptibly dulled. For small curves, lay the zinc on a piece 
of hard board, and with a pair of sharp pointed dividers the zinc 
can be scratched half way through its thickness, then by turning it 
over and placing the dividers in the same center, the other side may 
be cut in the same way, or so nearly through that it will break off. 
This affords a truer and more uniform curve than can be obtained 
in any other way. The legs of the dividers must be stiff and firm 
so as to be entirely free from vibration. After cutting, the sharp 
edges of the zinc may be dressed with a fine double-cut file, or better 
with fine emery cloth or sandpaper rolled over a wooden bolder. 

The lathe should always be stopped when testing the work with 
the template, and great care must be taken to make the two ends of 
the pattern symmetrical. When the turning is nearly completed the 
template itself may be tested by reversing the ends. If not true, it 
should be filed to the proper shape. 



PATTERN MAKING 



131 



Branches. The branch e must be turned in the same way as 
described for the main part of the pattern which is pared off, or 
planed off in a large pattern, to the exact size of the base of the 
branch, and when the pattern is large and heavy, one or two wood 
screws should be used in the tenon of the branch to assist in keeping 
it in place. 

In all small and moderate-sized valves the flanges are hexagonal 
in shape, as shown in Figs. 229 and 231. 

TwO'Part Core. The core for a globe vahe is made in two 
parts, and the core box for each part must be made in upper and 






Fig. 233. Upper Iron Core-Box Details 

lower halves, making four parts to the core box. This is necessary 
in order to allow for the removal of the core from the boxes. The 
internal shapes of the boxes are difficult to illustrate on paper, but 
if the drawings given in Figs..233 and 234 are carefully studied in 
connection with the sectional views of the valve shown in Fig. 230, 
their shape and construction should be readily understood. Three 
additional illustrations of the core as made in these core boxes are 
shown in Figs. 235, 236, and 237. 

Forms for Baking. If the form of the core is such that there 
cannot be a flat side upon which to bake the core, a metal form must 



132 



PATTERN MAKING 



be provided. The drying form can either be placed on the core 
after that side of the core box has been removed, or it can be the 
core box itself. For this reason, and because of the necessary wear 






Hg. 234. Lower Iron Core-Box Details 




Fig. 235. Dry-Sand Cores before Pasting Fig. 236. Sectional View of Dry-Sand Core 
Together 

and fragile character of wood for boxes of this kind, this core box 
will be made of iron. The wooden pattern for the metal core box 
must then have an allowance for double shrinkage, and to avoid 



PATTERN MAKING 



133 



excessive weight, the box is made iu the form shown in Pigs. 233 and 
234. In this form all unnecessary metal is removed, and lugs should 
be added to the upper part of the core box to align the two parts 
while ramming the core, as sho^Ti 
at 6, Figs. 233 and 234. The 
lov/er part of this core box, as 
shown, is to have projections cast 
on at a so that this half can be 
used for holding the core sand 
during the baking process. Sev- 
eral drying forms are furnished 
the core maker, if a considerable 
number of castings are 
required. 

Bonnet. Fig. 238 
illustrates the pattern for 
the stuffing box and bon- 
net of the valve, with 
core print turned on 




Fig. 237. Assembled Vicv,' of Dry-Sand Core 




Fig. 238. Pattern for Sluffing Box 




Fig. 239. Core Box for Stuffing Box 



each end, which, like the main pattern of the valve, must be parted 
or made in two halves. 



134 



PATTERN MAKING 



Core Box. Figs. 239 and 240 are illustrations of the core box 
and core for the stuffing box and bonnet. The process of building 

this core box is very similar 
to that used for the bronze 
bushing shown in Fig. 150. 
Saw the stock at a, 6, c, and d. 
Have the total length of all 
parts equal the total length 
of the pattern. Scribe the 
half circles on the ends of 
each piece, and gouge to 
form required. Glue all parts 
together, saw for splines, and 
complete as before. 




Drying Ping 



Fig. 240. Half Core of Stuffing Box with Drying 
Ring in Place 



1% 





Fig. 241. Valve Stem i^ut 



Nut for valve 



Fig. 242. Details of Valve and Valve Nut 




Fig. 243. Valve Spindle. (This pattern 13 not split) 



Drying Ring, A pattern for the drying form or ring should be 
made to the shape shown in Fig. 239, which is to be fitted into the 



PATTERN MAKING 



133 



core box at e. After drying the core, these rings are slipped endwise 
toward the chamber and then can be easily removed. 

SinaU Parts* The pattern for the nut for the bonnet is shown 
in Fig. 241, and those for the valve and valve nut are shown in Fig. 
242. The patterns should be so made as to form their own cores, as 
indicated by the dotted lines in the drawing. Fig. 243 is an illus- 
tration of the pattern for the valve spindle. 

Engine Cylinder 

Type of Pattern. The slide-valve engine is built in a great 
variety of forms. Fig. 244 represents a sectional view of the cylin- 
der of a very common type. At 
e, Fig. 245, we have a cross- 
section through the steam chest 
and exhaust port at AB, and 
at F, a cross-section at CD 
through the steam port. 

When the cyhnder is small 
— 10 inches or under in diameter 
— the pattern is usually built up 
solid, but if more than 10 or 12 
inches in diameter it should be 
built of staves, as shown in 
Fig. 246. When the size is 30 




Fig. 244. Section through Slide Valve Cylinder 



inches or over, a loam mold is usually made, as is fully described in 
the section on Foundry Work. The size limit, how^ever, varies 
greatly in different foundries. 





Fig. 245. Sections through Slide Valve Cylinder at .45 and CD, Fig. 244 



136 



PATTERN MAKING 



The construction of the pattern is illustrated in Fig. 246. and 
needs no description here, it being the same as already given for 





Fig. 246. Section of Cylinder Pattern 

Fig. 226. The flanges, however, should be built up of segments of 

two or three layers each, as shown in Fig. 247. , After gluing up to 

the necessary thickness to make the 
flange, it is sawed in two halves, 
jointed, and carefully centered on a 
wooden chuck, and turned to the 
dimensions required. The centering 
must be done with accuracy, or one- 
half of the flange ring will be larger 
than the other. 

Steam=Chest Pattern. The 
steam chest is next built and fitted 

centrally on the upper half of the cylinder pattern, as in Fig. 248. 

The projections a a, which give the extra width of metal for the 




Fig. 247. Built-up Flange for Cylinder 
Pattern 




Fig. 248. Two Views of Cylinder Pattern Including Steam Chest 

bolts of the chest cover, are left loose, being kept in place by long^ 
wires or dowel pinsi as shown at cc, so that they can be withdrawn 



PATTERN MAKING 



137 








E 


= ^ 


^===^^==^^ 


^;ri^^ — ~ > 


1 


i^ 




Wr^rn^i^'-^^y^rni-^rf^ 


^ 




separately from the mold after the main part of the pattern has been 
taken from the sand. These four strips should be recessed into the 
corners of the chest J inch, as shown by the dotted lines, to prevent 
them from being rammed out of place after the dowel pins are taken 
out. The boss i for the 
valve-rod stuffing box, 
and also the boss k 
around the steam-pipe 
opening, must be loose 
so as to be taken out of 
the mold after the pat- 
tern has been removed. 
The pieces oo at each 
end of the steam chest, 
which form a thickness 

of metal over the steam ^ ^ 

ports, are then fitted in ^^- ^^^^ ^^^^' °^ *^°'^ ^^^ ^^' ^^^^"^ ^^^^^ 
place, as is also the exhaust passage n, which must be parted on the 
line of parting of the two halves of the cylinder pattern. 

Core Boxes. Cylinder, The main core box for the cylinder is 
made in the same way as has been already described for Fig. 227. 

Steam Chest. The steam-chest core box is shown in Fig. 249, in 
which P is a side view, one side of the box being removed to show 
the valve seat v, and the core prints x, z, and y, which form recesses 
in the core into which the upper ends of the two steam-inlet cores 
and the central exhaust-passage 
core are placed. Q is an end 
view of the box with one end 
removed-, and i? is a view look- 
ing into the box from above. 

Exhaust Passage. For the 
core forming the exhaust pas- 
sage, two half-core boxes, one 
right and one left will be nec- 
essary. One-half of this box is illustrated at S, Fig. 250, as 
also a sectional view at T, The dotted lines show the manner in 
which the passage is widened to retain the full size of the opening 
throughout. 




Fig, 250. Exhaust Port Core Box 



138 



PATTERN MAKING 



Inlet Passages. Only one core box will be needed for the two 
steam ports. Three views of the box are given in Fig. 251. AtG 
one side is removed, giving a side view of the construction of the box. 
H shows a cross-section through G with the end u removed, and F is 
a view from above. The core is swept off on the upper side for the 
length of cc, and the bar ee as well as the end u must be movable so 
that the core can be taken from the box. Both ends of the core 
change from circular into straight parts just at the entering of the 
cylinder and at the entering of the steam chest. 

Facility of Construction. The entire set of patterns is simple 
and easy of construction if carefully made drawings are furnished 

to work from; the time 
and labor required de- 
pending entirely upon 
the size of the cylinder. 
Separated Steam 
Chest. In some slide- 
valve cylinders, the 
steam chest is cast sep- 
arate and bolted to the 
cylinder, thus affording 
free access to the valve 
seat V and a better 
opportunity for finishing 
and fitting. In this 
case, the main cylinder core and the two steam-inlet cores are 
made together in the same box, as illustrated in Fig. 252, in 
which one side of the core box is cut away to a depth of one- 
half of the length of the steam-port openings, or to the line cc, 
which must be just one-half of the inside width of the box, as shown 
at H and at F, Fig. 251. The part which has been cut away is 
replaced by the three blocks a, a, and b, which are shaped to give 
the required size and form to the steam-port cores. These blocks 
are fastened by dowels, loosely, to the main part of the core box, 
and, after the core has been rammed up, the whole box and core is 
turned over on its face and the main part of the box is lifted off, 
after which the two loose blocks a and a can be drawn away endwise 
and the block b can also be lifted out with ease. 




c7 /f 

Fig. 251. Views of Live Steam-Port Core Box 



PATTERN MAKING 



139 



GEAR WHEELS 

Accurate Teeth Required^ In this special class of pattern work, 
the greatest accuracy and care must be taken, not only in building 
up the rim of the wheel, but in fitting and placing on the rim the 
blocks out of which the teeth are to be formed, and most of all in 
laying out the teeth regularly and accurately on the tooth blocks. 
A pattern for a gear wheel whose teeth are carelessly made is almost 




Fig. 252. Bore and Live Steam-Port Core Box aa Arranged for 
Small Cylinders 

wortliless, the time lost in chipping and filing for the purpose of 
correction being too great to allow the use of such a pattern. 

Teeth Machine Cut It is common practice in some pattern 
shops to build the pattern with the teeth stock fastened to the rim 
permanently, and having the teeth cut in a gear-cutting milling 
machine. To insure greater accuracy and smoother running gears, 
it is now the custom in many shops to have the wooden pattern 
made in the form of a blank without teeth, from which a metal 
pattern is cast. This cast pattern is turned up and placed in the 
milling machine where the teeth are cut and spaced with accuracy 
and to the exact form of tooth required. This metal pattern is used 
without draft. This method of making gear patterns, however, is 
expensive, and is used only when many wheels are to be cast of the 
same size and number of teeth from the same pattern^ and, as in the 



140 



PATTERN MAKING 



case of pulleys, the wooden pattern is still used for all special sizes 
of gears. 

At its best, the cast gear can never compete with the cut gear 
for smoothness of running and the efficient transmission of power. 
The modern machine practice calls for machine-cut gears, and con- 
sequently the cast gear is only for certain classes, as slow-moving 
machines where considerable backlash can be allowed, and when 
the teeth can be of such size as to be molded easily. For these 
reasons, the present-day pattern maker rarely ever gets so far as to 
cut the teeth of the gear pattern. However, several methods of 
constructing the arms, rims, and teeth sections of these patterns 
will be considered, and a few hints given as to the best methods of 
construction. 

Patterned Teeth. Fomu As the form of the tooth used by 
the draftsman will play no part in the construction of the pattern. 




Fig. 253. Wood Spur Gear Showing Teeth Dovetailed to Rim 



we think it would be out of place here to enter into a discussion of 
the relative merits of the single-ciu-ve, double-curve, or other 
form of tooth. The single-curve or involute tooth, however, has 
the great advantage of being the only form of gear which can be 
run at varying distances between axes and transmit an unvarying 
velocity and amount of power. The common contention that two 
gears will crowd harder on their bearings when the single-curve or 
involute form is used has not been proven in actual practice. The 
practical methods for obtaining the curves for either the involute or 
for the epicycloidal tooth, the two forms in most common use, are 
taken up in Mechanical Drawing. In the illustrations here given, 
the single-curve form of tooth is used. 



PATTERN MAKING 



141 



Base line 



Fastening Methods, In the construction of gear-wheel patterns, 
the methods employed in making and fastening the tooth, or the 
blocks out of which the teeth are to be formed, to the rim of 
the wheel vary greatly. It 
was formerly the custom to 
dovetail the tooth into the 
rim of the wheel, as shown 
in Fig. 253. This, was the 
case especially when the 
teeth were large, as in 
2-pitch or larger. This is, 
however, an unnecessary 
expense and a waste of 
time, and, in addition, the 
cutting of the dovetails and 

the driving home of the dovetailed tooth often have the effect of 
distorting the rim to some extent. 

A better, or at least a more economical, method, is to fit the tooth 
blocks as shown in Fig. 254, which for strength and durability is 




^Pitch line 



Fig. 254. Wood Spur Gear with T^eeth Fastened with 
Wood Screws, Filler Pieces Glued between Teeth 




Fig. 255. Arms, Hub, and Core Prints of Spur-Gear Pattern 

found to be in no way inferior to dovetailing, and the saving of labor 
an4 time is very great. In this method we have always the advan- 



142 



PATTERN MAKING 




Fig. 256. Section Showing Rim Formation 



tage of a smooth clean fillet at the root pf each tooth, and having the 
grain of the wood, not only for the fillets, but also on the whole 
depth circle, run in the same direction as the grain of the wood which 

forms the tooth. This means a 

smoother pattern, more easily 

molded, and a better casting. In 

the former method, Fig. 253, it is 

almost impossible to form a fillet 

on each side of the tooth, as it 

runs off to a thin featheredge which continually splinters and chips 

off; still further, the bottom of the tooth space, that is, the whole 

depth circle is the rim of the wheel, composed of layers of segments 

with changing grain which will not mold so smoothly 

as in the second method. 

The blocks for the teeth. should always be cut in 
strips 2 or 3 feet in length, in order to season the wood 
so far as is possible while other parts of the wheel are 
being constructed. Only straight-grained wood should 
be used for teeth. 

Rim and Arms. The segments for building up the 
rim should be cut out next, then the arms put together 
and shaped as required. It is a good plan to fasten the 
arms central to the faceplate of the lathe, and to turn 
out a recess, say ys u^ch or ^ inch deep, to receive the 
hubs, as shown in Fig. 255. This makes a stronger con- 
nection and does away with the trouble of fitting and 
connecting the hub, with the thin featheredge of the 
hub fillet, to the surface of the web of the arms. The 
same method is of great advantage vrhen fitting the 
hubs of pulleys and other wheels. 

The arms must be put together, with inserted 
tongues in the joints, as illustrated and described in 
connection with Fig= 171; and if they are to be worked 
to an elliptical section, it is easier to do this before fixing 
them in the wheel. At A, Fig. 255, the construction 
of the arms is shown, and at B the core prints, hubs, and arms, with 
the manner of connecting these parts. 

After building up enough courses of segments to equal half the 



Fig. 257. 

Section 

Showing 

Facing of 

Tooth 

Backs 



PATTERN MAKING 143 

width of the rim plus half the thickness of the arms, the inside 
only of this part of the rim is turned out to the required shape, 
including the central rib a, Fig. 256, which must be of a thickness 
just equal to the thickness of the ends of the arms. The recesses to 
receive these ends are then cut into this half rim, and the arms fitted 
and glued in place, but not so tightly as to strain the rim and cau$e 
it to spring after it is removed from the chuck. Refer also to the 
method of building stock for arms and rims used in making the 
20-inch pulley, which has the advantage of requiring less labor. 
The remaining courses for the rim are now fitted and glued on, and 
the rim turned and finished to the required size and shape. 

Forming Teeth. Placing Blocks, 'The face should be glue 
sized to prepare it for the blocks which are to form the teeth of the 
gear. After sizing and re- 
moving the raised grain of 
the wood, the periphery of 
the wheel must be spaced 
for the required number of 
teeth. With a try-square 
and very sharp awl draw 

lines through the points ^'^'^'^' Spacing for Teeth 

obtained by the spacing, as shown in Fig. 257. Should the teeth 
be of moderate size, say 3-pitch or less, the tooth blocks should 
be glued on so as to meet each other on the rim of the wheel, as 
shown in Fig. 258, and, not being screwed on, must be nailed with 
brads from the face of each tooth into the rim after being shaped 
and finished. 

Each block must be so fitted as to reach only from line to line. 
Fig. 257, care being taken to have each block parallel to and coincide 
with its own line, reaching exactly to the line. When all the blocks 
are placed and glued, the wheel is returned to the lathe and the 
periphery turned off straight and to the required diameter for the 
addendum or tops of the teeth. The ends of the blocks are also 
turned even with the edge of the wheel rim, and before removing 
from the lathe, a circular line must be drawn on the ends of the 
blocks, on both sides of the rim, indicating the whole depth of the 
teeth. The use of this line will be explained later; it is the only 
circular line needed for laying out, or for working out the teeth. 




144 PATTERN MAKING 

When the teeth are large, a tooth block is first fitted on and 
screwed from the inside of the rim, as shown in Fig. 254, one edge of 
the block touching, but not covering its line on the face of the rim. 
The thin strip is next fitted^ glued, and bradded against the block, 
with the opposite edge of the strip reaching just to, but not covering 
the next line. A second tooth tleck is fitted and screwed in place, 
then a second strip, and this alternate placing of blocks and strips 
is continued until the surface of the rim is covered, having a block 
and strip for each tooth required. Care must be taken not to allow 
any glue to get between the blocks and the strips when gluing and 
nailing the strips on, as each block must be taken off, one at a time, 
after being laid out, to work the tooth to shape. 

Spacing. . Allien all the blocks and strips are in place, the wheel 
must be returned to the lathe and the face of the blocks turned to 
the diameter required for the addendum or tops of the teeth, and 
the ends of the blocks also turned even with the rim. The whole 
depth or clearance circles are marked, one on each side, while revolv- 
ing in the lathe, as explained for a wheel with smaller teeth. All 
parts of the rim should now be made perfectly smooth with fine 
sandpaper, using a holder or block to prevent rounding the corners 
or angles of the tooth blocks. 

Beginning at the middle of a block, space the required number 
of teeth on the periphery of the tooth blocks, and should the first 
trial not result in even spaces, the trial spacing must be continued 
until the greatest accuracy has been obtained, that is, until all 
distances from point to point are exactly equal. Through each 
spacing point, found as above, very sharp but light lines are drawn 
across the face of the blocks, as was showTi for the wheel rim in 
Fig. 257. When drawing these lines it w^ill be found best to draw 
along the inside edge of the try-square blade instead of the outside 
as is usual. . The reason for this is that on small or medium-sized 
wheels a much firmer base will be given for holding the square, 
and more accurate lines will be the result. A coat of shellac brushed 
over the ends and faces of the blocks, if sandpapered smooth after 
being allowed to dry, wall greatly assist in laying out. the teeth, 
hardening the surface, and enabling sharper lines to be drawn. 

Tooth Template. A template must next be made of the exact 
form of the tooth required. This will alwa^'s be given full size in 



PATTERN MAKING 



145 



the detail drawings furnished to the pattern maker. Should the 
wheel be of small diameter, the template may be laid out and cut 
on the end of a long strip of zinc, but it is better to fasten the tem- 
plate to the end of a wooden bar, as shown in Fig. 259, a narrow slot 
having been cut through the back end of the zinc to allow of exact 
adjustment to the diameter of the wheel. ^^ This wooden bar is hung 
centrally on a peg or dowel which must be placed exactly in the 
center of the hub. For this purpose it is customary to use a block 
of wood as a temporary hub, the center of which may be easily 
found from the periphery of the blocks by the dividers. A very 
slight sharp notch i? made in the exact center of the end-of the tooth 
template, which must be radial to the hole in the opposite end of 




Fig. 259. Template Used to Lay Out Teeth of Spur Gear 

the bar on which the template revolves. This notch is shown in 
Fig. 259. 

To use the template, place it over the center pin and bring the 
notch exactly in line with one of the spacing lines on the outside 
of a block, and with a very sharp pointed awl mark the tooth on the 
end of the block. . Then swing the template to the next line and 
mark as before, continuing the process until a tooth has been laid 
out on the end of each block. The wheel is now turned over and 
the same process repeated on the other side. It will be readily seen 
that if the spacing lines have been squared across the face of the 
wheel with accuracy, the teeth laid out on the two sides will be true 
and perpendicular to each other, a spacing line forming the exact 
center of each tooth, and for this reason these lines should always be 
very light but sharp and clearly defined. 

Cutting and Paring. For convenience in cutting and paring, a 
second series of lines should now be drawn across the face of each 



146 



PATTERN MAKING 



block connecting the extreme ends of the lines which describe the 
shape of the tooth on each end of the block. Should the wheel be 
small and within the capacity of the band saw, all superfluous wood 
may easily be removed from between the teeth. 

If the band saw is sharp and evenly set, and the operator skill- 
ful, the teeth may be sawed so as to need but very slight correction 
with the paring chisel and gouge. As the hubs usually project 
beyond the rim on each side of the wheel, they should be left loose 
and removed before placing the wheel on the saw table. 

For large wheels and heavier teeth, each tooth block should be 
imscrewed and removed, one at a time, and planed to the lines 

marked on its ends and 
face, after which it is 
returned to its place 
before a second one is 
taken off. This is con- 
tii;iued until all the teeth 
are shaped, when it will 
be necessary only to 
construct fillets at the 
base of the teeth, and 
also to w^ork each space 
down to the whole depth 
or clearance circle, the 
circle having been drawn 
for this purpose and also as a guide for bringing all tooth spaces to 
the same depth! 

Solid Pinions, Small gears, or pinions, as they are called, are 
usually made with a solid web instead of arms, and are glued up in 
solid blocks of end wood, the grain of the entire block running parallel 
with the face of the teeth. Such an end-wood pinion is shown in 
Fig. 260. It is turned and the gear laid out and cut in the same way 
as described for the larger wheels, except that, the teeth are not 
glued on but are cut out in the solid disk. 




Fig. 260. Section Showing Small Gear Made 
from Glued-Up Stock 



Bevel Gears 

Built»Up Construction. Patterns for bevel and miter gears are 
built as illustrated at a and h, Fig. 261. The segments are to oxerlap 



PATTERN MAKING 



147 



as shown, which is not only a saving of stock, but also saves time 
which would be required to turn the angular rim from a square 
construction* It will be best to make a full size Ijiyout of a radial 





Fig. 261. Large Bevel and Miter Gears Conr 

structed of 8uilt-Up Stock and Turned on 

Faceplate 



Fig. 262. Section of Miter 
Gear, Shown Screwed to 
Faceplate for Turning 



section of hub, arm, rim, and tooth. Marking the thickness of 
segments on this layout will show the diameter dimensions, which 
can be taken directly from the layout. 

Rim. The process of gluing the segments will be the same as 
used for the pulley rims previously considered — gluing paper between 
the faceplate and the first layer of segments, and also nailing through 
the segments into the faceplate, or placing wood screws through the 
faceplate into the first layer of segments. When a sufficient number 
of courses have been glued together, including the temporary fitting 
of the arms, the face / and the edge e are to be turned to correct 
angle and diameter. Make a template for the angle shown in 
Fig. 261, taking the dimensions from the full-size layout. The rib 
c, which will finally be a continuation of the arms, is also turned to* 



148 



PATTERN MAKING 



shape and to the thickness of the ends of the arms. The rim will 
then present the appearance shown at b, Fig. 261. 

Remove the rim from the faceplate and nail and glue six blocks 
to the faceplate. Turn these blocks to the inside diameter of the 
ring c and fasten the rim to the faceplate with six clamp pieces, 
shown at d, Fig. 262. In this position the edge g and the inside of 
rim h is turned and finished as shown. It is not necessary here to 
describe the method used in finding the required angles for the face 
and edges of the rim, but, as in the case of spur-gear teeth, the 
student should refer to Mechanical Drawing. 

Drawing Arms. The arms, partly shown in Fig. 263, are next 
fitted and fastened to the rim. It is well to glue a small disk on 
each side of the web of the arms, as shown, which not only strength- 
ens the arms, but serves as a fillet 
around the hub of the wheel. 

Loose Pieces. In Fig. 264, the 
hub // and the ribs of the arms 
RR are often made loose so as to 
lift with the cope, which is of 
great advantage in molding. 

Fitting Teeth. The blocks for 
the teeth are next fitted in place, 
either as illustrated in Fig. 264, or 
in the form of alternate blocks and 
strips as was shown for the spur gear. Fig. 254. After all the blocks 
are in place, the wheel must be put in the lathe and turned to the 
sizes and angles required for laying out the teeth. A sharp line 
must be drawn on the face of the blocks, while in the lathe, to serve 
as a guide for the dividers while spacing the teeth. 

Use of Centrolinead. To obtain the center lines for the tooth 
faces after spacing on the blocks, it will be readily seen that the 
ordinary try-square cannot be used as in the case of the spur gears. 
A temporary square or centrolinead may be made for this purpose 
as follows: 

Take a piece of hard wood about 6 inches long, 3J inches wide, 
and J inch in thickness. Dress the two edges perfectly parallel and 
from the upper edge a, Fig. 265, with a try-square and a sharp 
pointed knife, draw the line c, equally distant from each end of A, 




Fig. 263. Part of Arm Pattern for 
Miter Gear 



PATTERN MAKING 



149 



and at right angles to the edge a. Lay the edge b oi A against 
another board B, of the same thickness, and continue the line c on 
this board, as shown by the dotted line. With the dividers set 
on the extended line c on the board B, and with a radius equal to 
the longest distance of the outside edges of the tooth blocks from the 
gear center, describe the arc xy on A> Cut the edge h to this arc. 





and see that it perfectly fits 
the outer rim of the tooth 
block. Next make a thin 
blade of hard wood and screw 
it to the head A, using the 
greatest care to have one edge 
of the blade coincide exactly 
with the line c. After screw- 
ing the blade to the head, its 
accuracy may be tested by 
placing a try-square against 
the edge a. The result will 
be as shown in Fig. 266, in which the edge c is radial to the arc 
xy. This edge will describe the center lines of the teeth radially, 
as required. 

This temporary square can be used, within the limit of its blade, 
on wheels of larger diameter than that to which it has been fitted, 
but cannot be used for smaller wheels. For the larger gears the 
position will be as shown in Fig. 267, which will give the correct 



Fig, 264. Section of Miter Gear, Showing 
Stock Assembled for Teeth 



150 



PATTERN MAKING 



perpendicular if the angles at x and y are carefully made. By using 
in this way, only a few squares will be needed for a great number of 
wheels. 

Fastening, When the teeth are 
large, they must be screwed on from 
the inside of the rim. If small, they 
should be bradded from the outside 
or face of the tooth into the rim after 
the teeth have been shaped and 
finished. 

Templates. Two templates will 
be necessary for laying out the ends 
of the teeth, the outer ends being 

Fig.2C5. Construction of Template ^^^^^^ ^^i^^ ^^^ '^^^^^^ The Se tem- 
plates are made as described for spur gears, and have the outer 
end bent to fit over the angles of the rim. 






Figs. 266 and 267. Templates for Face of Teeth 



COLUMNS 

Patterns. Cast-iron columns are often ornamented or fluted as 
shown in the half section of a fluted column in Fig. 268. In all^uch' 
cases the body of the pattern is made octagonal, as shown by th^ 
outline ABODE, The loose pieces forming the flutes are held to 
the main body by pins that stand at right angles to the line AE, 
After the sand has been rammed, the body included in the outline 
ABODE may be lifted out, [leaving the parts AahB, BhcO, etc., 
imbedded in the sand; then, one after another, these latter may be 



PATTERN MAKING 



151 




Fig. 268. Section of Ornamental Col- 
umn Showing Loose Pieces 
Picked-la 



lifted out. These fluted sections should never be so few in number 
that they cannot be lifted out without tearing the sand. Eight or 
twelve sections will be needed. 

Other forms of ornamentation 

a 

are put upon columns- in a similar a' 
manner. Leaves or flowers are held 
by pins or in grooves in such away 
that the main body of the pattern 
may be lifted out without disturb- 
ing them, and they then may be 
withdrawn from the sand through 
the cavity left by the main pat- 
tern. 

Cores. Cores for columns may 
be made in core boxes as in the 
case of those for pipe, but where 
the core is long and straight no core 
box is needed. The core is usually 
bui't of loam about an iron pipe, as 
explained in Foundry Work. 

Where the core is to follow the 
lines of the ornamental moldings on 
the outside of the column, it may 
be provided with a special core box 
or better with a sweep, as shown in 
Fig. 269. This sweep is used to 
shape the loam core that is to be 
built up on an iron pipe. Fig. 269 
Is the outline of the template that 
is to be used in sweeping the core 
for the interior of the columns 
shown in Fig. 270. 

Follow Boards, All thin pat- 
terns that are likely to suffer dis- 
tortion from the pressure of the 
sand, while being rammed up, must 
be provided with accurately fit- Fig. 269. strike, 
ting follow boards. These follow core Lr'coiumn 




Fi^. 270. Completed 
Uolumn Pattern 



152 



PATTERN MAKING 




boards may be made to fit ,on either one or other of the sides of the 
pattern. 

When the outlines of the pattern are very irregular, the follow 
boards are often made of plaster or other eomposition, which, when 

dry, is used to support the pat- 
tern while the drag is being 
rammed. 

Fig. 271 represents a section 
of a railing cap. If the pattern 
B were to be set with the edges a a resting upon the molding board 
and the sand of the drag rammed down upon its upper face, it would 
be sprung out of shape. To avoid this the follow board A is made 
to exactly fit the imder side of the pattern. Then when the sand is 
rammed, the whole pattern is supported and there will be no dis- 
tortion. When the cope is rammed, the follow board is removed 
and the sand of the drag supports the pattern while the cope is 
being rammed. 



Pig. 271. Follow Board 




w H -I 






50 (S ^ 



PATTERN MAKING 

PART III 



COMPLICATED PATTERN CONSTRUCTION 

HAND= AND MACHINE=MOLDED EXAMPLES 
HAND=/VlOLDED HYDRAULIC TURBINE 

Conditions, This class of work requires a very clear concep- 
tion of the principles of pattern making. The working drawings 
are for the completed casting as usual, Fig. 272, while the several 
core boxes are designed and constructed by the pattern maker. 
Extreme accuracy must be exercised, for the slightest variance 
will be noticed when the cores are assembled, and also in the results 
of the output and efficiency of the turbine when installed. The 
type of turbine shown is adapted to fairly high head or fall of the 
water, relatively small power output, and low speed. The form 
of the guide vanes and rotor vanes — the latter commonly and 
erroneously called buckets — shall be furnished by the designer, 
and a sheet-zinc or brass template should be made to this design. 
If possible, have the designer check these templates and have them 
carefully stamped with the diameter and other data, so that they 
may be readily identified. 

In all the illustrations, like letters will denote like parts. 
Fig. 272 is the working drawing of the guide ring, showing the 
principal finish dimensions. No attempt will be made to give 
data for the form of the vanes, but the shape shown will be close 
enough to that used in practice, for the considerations of the pattern 
maker. To have it clear just what is being built, it should be 
understood that the rotor ring is the revolving portion, while the 
guide ring is stationary, and that water passing through the guide 
ring from outside to inside continues on through the rotor ring 
and discharges into and out through its center. The guide ring is 
bolted to the casing and the rotor ring is bolted to the rotor hub. 
The casing and hub are not shown. 



154 



PATTERN MAKING 



Durable Core Boxes, The core boxes for the guide vanes are 
often made of wood, having those parts which are subjected to the 




3eciion/J/J 
Fig. 272. Plan and Radial Section of Guide Ring 

most wear lined with sheet brass, or perhaps hard wood. These 
boxes are not made of solid glued stock, but are framed together 
in such a way as to prevent as much as possible of the distortion 
due to shrinkage. However, in our consideration it is intended 
to produce a set of core boxes for these castings which may be used 



PATTERN MAKING 



155 



for years. The core boxes for the guide and rotor vanes will be 
constructed of cast iron, for these parts of a turbine are often required 
to be replaced, and wood core boxes are liable to become distorted 
and wear out of shape so as to give unsatisfactory results. 

Guide Ring Coring 

Guide Vanes, The illustrations and descriptions are for the 
guide-ring casting; the equipment for the rotor-ring casting being 
very similar to that for the guide ring except in dimensions. Fig. 273 
is a plan view of two cores, set together so that the space between 




Fig. 273. Top View of Two Cores for Guide Ring 

forms the mold for one of the guide vanes. The radius d is the 
outside of the ring casting, including the finish allowance, and c 
is the inside of the casting, including the finish. The difference 
between the radii o and r equals the radial width of the dry-sand 
core. This is also indicated in Fig. 274, where are shown the core 
box halves. The radial dimensions denoted by the differences 
between d and o, and r and c depend somewhat on the diameter 
of the ring; for a guide ring with outside diameter of about 5 feet, 
this radial difference should be 2 J inches each. 

Template, On a new sheet of zinc carefully lay out arcs with 
the radii o, d, c, and r, and the form of the face and back of the vane 



156 



PATTERN MAKING 



per data given by the designer. The chord e must be carefully 
spaced to give the proper number of vanes. Multiply the diameter 
of the outside of the cores by the sine of \ of the included angles 
for this chord length. As a dry-sand core swells slightly while it] 
is being dried, this chord e should be made a little short of the figured 




Fig. 274. Plan and Elevations of Iron Core Box 



length. Experience is the best teacher as to how much should be 
allowed for this expansion, different mixtures of core sand, hardness 
of ramming, and rate of drying, all having effect, and the bottom 
of a core expanding more than the top, due to settling from its own 
weight. Make the chord e i% inch short for this casting. Siicteea 



PATTERN MAKING 



157 



vanes are shown in Fig. 272 so as not to appear too complicated, 
but twice this number would be nearer that used in practice. The 
wooden pattern for the core box is to be made double shrink — J inch 
per foot — so double shrinkage should be allowed when laying out 
the form of the zinc template. The form of this template is shown 
in Fig. 273 by the letters tttt, and another template with singly 
shrink of | inch per foot, should be made for checking the dimen- 
sions of the iron core box. 

Vane Core Box. Flanged Sides, Preliminary to making the 
durable iron core box. Fig. 275, prepare stock for the flanges for the 
wooden core box f inch thick, obtaining the form and dimensions 




Botiom 
Plate 




Fig. 275. Diagram of Completed Iron Core Box 



Detail of 
Locking J>9vitf» 



from the double-shrink zinc template, and making the inside edge 
I inch outside of the template so as to run the stock for the outside 
wall from bottom to top, as shown in Fig. 276. The perspective 
sketches in Figs. 275 and 276 illustrate the appearance of these 
flanges, the pieces j and k being sawed to the full length and the 
tenons produced with the machine saw. The grain of the stock 
should be as nearly parallel to the length of each piece as possible. 
The layout for these flanges need only be made on one piece 
of stock. Nail two or more pieces of stock together, as the needs 
may be, band sawing all from the one layout. In nailing stock 
together for this purpose, use two slim finish nails and drive them 



158 



PATTERN MAKING 



one at each end — not near each other at the center, and not in the 
waste stock. These same nails will then hold the pieces firmly 
together while the edges are being trimmed smooth and true. Should 
the depth h be over 12 inches, an intermediate flange should be made 
and placed between the openings m and m. Glue j and ji together, 
using care that the angle between them is correct. ' A slight draft 
should be made on these flanges, the outside edges being the thinnest. 

With stock for the 
pieces wio dressed to size, 
the flanges are nailed and 
glued together, as shown 
in Fig. 276. All parts 
should be hand-planed 
before they are assem- 
bled. Always nail each 
joint in correct location 
— driving the nails only 
far enough to locate each 
piece — before the glue is 
applied. When the nails 
are driven through the 
joint after the glue is ap- 
plied, the glue acts as a 
lubricant for a few sec- 
onds, causing the parts 
to slip, and some of the 
glue will be pressed out 
of the joint so as to ob- 
scure the construction lines, with the result that often a joint will 
be finally fastened together a little out of position. 

Another rule that must be followed by the accurate pattern 
maker is never to use a lead pencil or a scratch awl for marking 
center and construction lines; use a thin pointed knife and make 
sharp deep lines. Pencil lines are too broad, and the awl tears 
the stock. Center lines should always show on the surface of the 
completed pattern, but construction lines should not, unless they 
mark the location of some future alteration or addition. The 
eerier lines arejiecessary for checking the dimensions of the pattern. 




Fig. 276. , FlangC9 and Partially Assembled Rear Half 
of Core-Box Pattern 



PATTERN MAKING 



159 



Having the flanges assembled, nail and glue the walls x in 
place. This stock is to be I inch thick, with the grain running 
vertically. Where the radius is short, narrow pieces should be 
used as shown. The work on the opposite half should be carried 




strike 



Fig. 277. Vertical Sectioa of Core Box on Line i i, Fig. 274 

on at the same time. Smooth the inside of each half and the whole 
to fit the template. 

Slots and Draw Pieces. The slots vim shall be carefully laid 
out to the dimensions a and b, shown in the vertical section of tlic 
core box. Fig. 277. Bore holes at each end, and saw with a thin 
backless saw. It will be necessary to start the cut with a keyhole 
saw. The edges should be 
trimmed with a chisel and have 
a decided draft to each side, as 
the slot is molded with a green- 
sand core. See that there is no 
back draft at the ends, and to 
prevent this, the slot should be 
made shorter than the required 
width, being filed out in the 
casting. 

A pattern for the draw 
pieces I and Z is to be made as shown in Figs. 274, 277, and 278; 
the radii c and d being shown in Fig. 272. The thickness is u, and 
an enlargement at one end is provided to serve as a handle. Two 
castings from this pattern are required, 

Bottom. Plate, A cast-iron bottom and top will require a 
right- and left-hand pattern, illustrated in Fig. 279. Stock should 
be glued of narrow pieces, say 3 inches wide, with the heart side of 




Fig. 273. Draw Pieces for Core Box 



160 



PATTERN MAKING 




the stock reversed, and should be cut to the form shown in Figs. 
275 and 279. The small blocks or lugs are so placed that they cen- 
ter the bottom with the sides. This bottom can be centered with 
the sides by dowel pins in holes drilled through the flange. How- 
ever, as the bottom and top should extend outside of the flanges, 
to provide means for lifting, there will be plenty of room for 
these lugs. 

The piece y which forms the mold for the upper and lower crown 
is glued to the plate, and stock should be removed with carving 

gouges from the opposite 
side to prevent as much 
weight as possible. This 
piece is sawed to the 
form of the template and 
the radii c and d. The 
face shall be carved to 
the bevel and round cor- 
ner shown in Fig. 272. 
A radial template of thin 
wood can be made to 
show the form of this 
surface. If the template 
with its edge coated with 
blue chalk is passed over 
this surface, it will indi- 
cate the high spots. 
These can be reduced with the carving gouges until nearly to dimen- 
sion, when the surface should be smoothed with one of the flat 
iron spokeshaves. 

Stop-offs, shown in Fig. 279, should be screwed to the outside 
of these wooden patterns to prevent warping. They should have 
liberal draft, say about 3 inches to the foot, and should be finished 
to some color different from the body or core-print portions of the 
pattern. The imprints of these stop-offs are filled in after the 
pattern is drawn, and do not come in the casting for the metal 
core box. 

Pouring Gate, The block p. Fig. 279, forms a pouring gate 
and generally is used in four of the cores. It can be made of hard 




stop Off^ 
Fig. 279; Bottom of Vane Core Box 



PATTERN MAKING 



161 



wood or iron, and is held in place by two small steel dowels. The 
pattern maker should consult the molder for the dimensions of 
this gate. 

The gate continuation should be made of a dry-sand core, 




Loose Piece 
Vig. 280. Perspective View of Core Box for Gate with Side Removed 

which IS shown in Fig. 286, and the core box for which is illustrated 
in Figs. 280 and 281. 

Core-Box Top. The top of the core box is made to the same 
dimensions as the bottom, but is made the opposite hand. The 
gate p is to be fitted to both bottom and top. 

Use of Core Box. These guide rings are made both for turbines 
which rotate in a right-hand direction and also for left-hand 




(Loose Pic'cc 



^^^ 



/-J 
Fig, 281. Details of Core Box for Gate 

rotation. The same core box can be used for both; consequently 
what 13 the bottom of the core for the right-hand turbine 
becomes the top of a left-hand turbine. 

The hooks for locking the box together, while ramming the core, 
are iron or soft-steel forgings and can be fitted by the metal-pattern 



162 



PATTERN MAKING 



maker. In ramming the core, the sides are clamped together and 
placed on the bottom. Core sand is rammed to the underside of 

the lower draw piece, 
and is then struck off 
with the strike shown in 
Fig. 277. Inserting the 
draw piece, the ramming 
goes on and the strike is 
again used when the up- 
per draw piece is reached. 
With both draw pieces in 
place, the box is rammed 
to the top. Using the 




Fig. 282, Elevation of Guide-Ring Core Looking from 
Ring Center Outward 




Fig. 28iSL_Core Box for Bottom Core 



strike, it is possible to ram the 
sand firmly under each draw 
piece, where it would be rather 
difficult to ram in any other 
way. Sand is now cut out at 
the top nearly to the shape of 
the. top crown, and the top of 
the core box pressed into place. 
This top may have to be re- 
moved several times until the right amount of sand has been 
removed. When the top of the core is completed, the space form- 
ing the top crown of the ring is filled with green sand, a drying 




Fig. 284. Details of Bottom Core 



PATTERN MAKING 



163 



plate placed on top and the core box and all are rolled over. The 
bottom can now be removed and the draw pieces drawn out through 
the side, forming the mold for the intermediate crowns llf Fig. 272. 
The sides can now^ be taken from the core, which appears as 
in Fig. 282. 

Bottom Core. The core box for the bottom core is shown in 
Fig. 283, and the core in Fig. 284, and in the radial section of the 
assembled cores, Fig. 286. The number of flat cores to go around 
should not be the same as the number of vane cores, but enough 
to give an outside chord length of about 20 inches. The dimen- 
sions of this core, shown in Fig. 284, are not arbitrary, and should 
be made to correspond to the requirements of the weight of the 




^^ Diameter of 
Jp/nd/e 



Fig. 285. Gage for Setting Bottom Cores 



vane cores. The illustration of the core box shows the construc- 
tion; the thickness of the bottom should be about | inch, and the 
sides about 1| inch. The bottom can be made of pine or mahogany, 
and the sides of mahogany, maple, or birch. 

Radius Gage. A measuring stick, Fig. 285, must be provided 
to locate the bottom cores. The semicircular notch at the inner 
end shall be the diameter of the spindle, which should be about 
3 inches, and a small block should be nailed and gluied on, or a notch 
cut in one edge, at the outer end. The radius r should be the same 
as the inner radius of the vane cores. 

Cover Core. The covering core a*, in Fig. 286, can be made 
in the core box for the bottom core by fitting a loose piece s, as 
shown in Fig. 283, into the core box to stop off the shoulder. 

Molding Process. After bedding the drag flask in the foundry 
floor, a spindle made of a piece of steel shafting, bolted in the hub 
of an old pulley, or any other method \Vhich will hold the spindle 



164 



PATTERN MAKING 



in a vertical position, is bedded in the sand at the center of the 
flask. The sand inside the flask is rammed hard and struck off 
level to form what is called the bed. The spindle must stand ver- 
tical to this bed. Place the bottom cores on the bed and set them 
concentric with the spindle, using the measuring or gage stick, 
Fig. 285. Upon these cores the vane cores are placed, and the 
covering cores are placed on top of the vane cores. The spindle 
then is drawn out and the gate cores set. A portion of the shoulder 
on the bottom cores will be cut out to complete the gate into the 
mold, as shown in the assembly, Fig. 286. The sprue is made with 
a tapering wooden pattern placed in position at the jimction of the 



Co\/»rin^ Core 






Cor&d 0a i& (q) 



Fig. 286. Radial Section of Guide-Ring Core on Line //, Fig. 273 

gate cores. Iron or wood cheek flasks are placed outside of the cores, 
and rammed full of molding sand. The cores are thus held securely 
in place and the mold is made without having to turn the drag mold 
over, which is quite an advantage in heavy work of this class. 



MACHINE-MOLDING PRACTICE 

Adaptation to Production. The adaptation of patterns to the 
present-day demands on the foundry for large output of duplicate 
castings makes it imperative to so arrange the equipment that the 
largest number of castings per molder-day shall be obtained. This 
will reduce the labor cost per casting, and where machine molding 
does not increase the output, it will be possible to employ imskilled 
workmen, which will lessen the cost. To accomplish this, various 
arrangements of the patterns have been worked out and the castings 
all come imderthe heading of machine molded castings. 



PATTERN MAKING 165 

Special Study. The concern manufacturing molding machines 
often contracts to mount on their machines such patterns as are 
required, and in that case the design and molding operations are 
worked out by the designing department. However, in many pat- 
tern shops the adaptation of the patterns is left wholly to the pattern 
maker. Now the study of the problems presented is such that the 
pattern maker soon becomes a specialist, and, if just taking up this 
work, it will be well to consult the foreman of the foundry, for 
many questions will arise where the pattern maker would find it 
difficult to give a practical decision. 

Every class of castings calls for a different solution about 
the equipment that makes the work special. A machine mounted 
pattern that is a success in one foundry will often be a failure in 
another. A pattern fitted for machine molding, with the expectation 
of an order for 1000 castings, probably would not be the same 
arrangement if the order were for 100,000 castings. Greater 
expense could be put into the pattern equipment for the larger 
order, and should be done if the output could be increased. 
The output per day should be considered, and where a number 
of small duplicate patterns can be molded in one operation, the 
flask should not be so large that the operator cannot handle the 
mold easily. 

All in all, this field offers a study of molding and the pattern- 
making propositions not found in the usual classes of hand-molded 
patterns. To attempt to offer a complete work on this branch 
of pattern making would be folly in the extreme. The personal 
experience of any one expert would require a large amount of space, 
and the possibilities would only be touched upon. 

Increased Uniformity. The changes that have taken place 
the past few years in the process of machining steel are also evident 
in the methods of machining castings. In machining large nimabers 
of duplicate castings the machinist resorts to jigs for holding the 
piece while the work is being completed. It is the case that hand- 
molded castings will vary in dimensions to some slight amount, 
due to the slight difference in rapping during molding, which cannot 
always be kept constant. Patterns are sent first to one foundry 
and then to another and made today by one molder and tomorrow 
by another. Even if a machine-molding equipment does not 



166 



PATTERN MAKING 



increase the output, the unifonnity of castings and the unskilled 
labor that can be employed will generally pay for the outlay, 

USE OF PATTERN PLATE 

Bearing-Cap Pattern. Shrinkage. For the use of a pattern 
plate with the pattern for the ring-oiling ball-and-socket shaft- 
hanger bearing cap, Figs. 
287 and 288, the process 
of constructing the 
wooden pattern is identi- 
cal with that for a hand- 
molded pattern, except 
that two shrink allow- 
ances are to be made. 

If the final bearing cast- 
Fig. 287. Cap for Hanger Bearing • • 4.^ i ^ ^( :^^^ „« 

^ K 6 6 jj^g ^g .j-Q ^Q Qf iron, an 

allowance of yV inch or J inch per foot will be made for shrinkage, 
and if the metal pattern is iron, double this amount. With an 
aluminum pattern, the combined iron and aluminum shrinkage, 
amounting to f inch per foot, must be allowed for. 

Stock Preparation. For best results the stock should be 
glued of several pieces, as shown in Fig. 289, reversing the heart 






.Q^^ionan line &3 



End View 



Fig. 288. Working Drawing of Cap for Hanger Bearing 

side of each piece, and using only very dry and sound stock. Dress 
the glued stock to a parallel thickness and width. The width shall 
be equal to d, the height c, and the length e. The edges shall be 
dressed square with the two sides, and longitudinal or transverse 
center lines are to be laid out on all surfaces. 



PATTERN MAKING 



1G7 



On the working face the complete outline of the pattern should 
be made as illustrated by the lines h in Fig. 289. On one edge 




Fig. 289. Partially Completed Stock for Cap Pattern 

produce a layout showing the height or thickness of the pattern, 
as illustrated by the line i: 

Forming, The semicircular hole is cut out with a core-box 
plane, to a diameter of t, which is larger than the shaft, as this is 




. Wood screws 

Fig. 290. Cap Pattern Stock Mounted on Wood Arbor Ready to Turn Outside 



•a babbitted bearing. Band saw to the line i, leaving stock at jj 
so that when band sawing to the lines h h the top surface or working 
face of the stock will be kept parallel to the table. The stock at 
j may be cut off with a chisel after the band sawing is completed. 




168 PATTERN MAKING 

Prepare an arbor and fasten the pattern to it, as illustrated 
in Fig. 290, with six wooden screws. The pattern may now be put 
into the lathe, and all parts that are concentric with the arbor 
mm, nn, and /, may be turned. The lathe should be run at its 
slowest speed and the turning done with a narrow square-nose 
chisel. The parts kk, which are over the recess for the oil rings, 
should not be turned. The surfaces m m and nn can be worked to 

size by trimming to a template, 
but the suggested method 
of trimming will work out very 
well and produce accurate 
results. The stock at I is[to be 
cut down to the diameter of 

Fig. 291. Preparing Stock for Babbitt Ledges ^^^ pattcm at 71, and at 0, 

where the center lines which were made on the squared stock inter- 
sect, the center of the boss q, Fig. 288, should be found. 

The babbitt ledges r. Figs. 287 and 288, are semicircular rings 
band sawed from stock of the required thickness, Fig. 291, and 
the grain of which should be as illustrated. This gives the greatest 
strength to these parts after they are nailed and glued in place. 
One small finish nail at each end will be all the nailing required, 
and the inner diameter will be smoothed on a sandpaper roll. The 
flanges vv, Figs. 287 and 288, are thin strips of stock glued into a 
rabbet sawed after the turning is completed, and this flange is cut 
out so as to leave the rim w. The oil cups are turned and fitted 
into the holes p. Fig. 290. The recesses uu, Fig. 287, are carv^ed 
with gouges, and the form determined by the use of a template. 
A little blue chalk on the template will indicate where the stock 
is to be removed to obtain the correct form. 

Making Pattern Plate. The equipment that the moldep will 
require to mold this pattern plate will be a mold board, a pattern 
for the plate, and four strips of wood to nail to the parting edge 
of the wood flask. 

PaMern Board. The pattern board, an illustration of which 
is shown in Fig. 292, should be made of pattern stock. Upon 
locating the pattern, fit and nail the pieces a: a; in place. In the section 
view, Fig, 293, the form of these pieces is shown more clearly. They 
form the coped parting, which in hand-molding is cut out by hand, 



PATTERN MAKING 



169 



or is fonned by a sand or a plaster match. The ribs w w should 
be fitted into the mold board so that the flange v will rest upon 
the mold board. 

Plate Frame, The pattern for the plate is an open frame 
about I inch thick. The opening should be large enough to fit 




Fig. 292. Pattern Board 

over the pattern and the parts of the mold board marked x x. The 
extension at each end should be large enough for the flask pinholes, 
and also serve as handles. The other portions of the plate pattern 
should not be larger than the flask. 

Molding Metal Pattern and Plate. After ramming the drag 
mold, it is turned over onto a bottom board, and the pattern board 




Fig. 293. Section of Pattern Board 

removed, leaving the cap pattern in the mold. The cope mold 
then is rammed and removed, followmg which the plate pattern 
is placed on the parting, and strips o£ wood the same thickness as 
the plate pattern are nailed to the edges of the flask. The drag 
mold at this stage has the appearance illustrated in Fig. 294. 



170 



PATTERN MAKING 



Molding sand is now rammed into the space between the plate 
pattern and the flask, forming a new parting i inch above the parting 




Fig. 294. Drag Mold of Cap for Hanger 

made by the pattern board. The cap and plate pattern then are 
removed and the gates cut. 

Closing the cope forms a mold that will produce a pattern plate, 



no6h Pin • 




Vibrator Affached Here 

Fig. 295, Completed Plate Pattern 



an illustration of which is shown in Eig. 295, and on the reverse 
side of which will be the opposite^ side of the cap pattern. 



PATTERN MAKING 



171 



Use of Steel Frame. A system used in some foundries is to 
have a steel frame for the plate pattern, and, leaving this frame 
in the mold, cast the pattern and the balance of the plate of alumi- 
num, or some special alloy. This process produces a lighter weight 
plate and it is intended to melt the pattern out of these steel frames 
in case the pattern becomes obsolete. 

Gate, The pattern for the gate illustrated in Fig. 295, at y, 
may be fastened to the pattern board and cast on the plate, or cast 
of brass separately and fastened to the plate with two machine 
screws. This last method allows the gate to be readily removed 
and altered should a change become necessary. 

STRIPPING DRAW-PLATE MACHINE 

Flange=Coupling Pattern for Hand Molding. In Fig. 296 is 
illustrated one half of a flange coupling such as is commonly used 
on mill shafting. Fig. 297 
illustrates a radial section 
view of a pattern for hand- 
molding this coupling. 

Wooden Constniction. 
The web is to be made of 
glued and splined segments, 
as recommended for the web 
of the disk crank in Part 11, 
Pattern Making. A shoul- 
der is turned at the edge of the web to receive the rim, which is 
built of several layers of segments, the whole being turned on a face- 
plate. The hub d and core prmts e and / are to be made loose. 
The hub stock will have a 1-inch hole through its center and be 
turned on a hard-wood or steel arbor. A rabbet is turned at one 
end, and five or six segments fitted, glued, and nailed into this 
rabbet to form the stock for the fillet. The hub should have a 
normal draft — | inch- per foot — and a small chamfer or rounded 
edge on its outer end. The grain of the stock should be parallel 
to the axis of the hub, whether the stock is made of glued stock or 
not. The dowel pin m should be glued in the hub. Having 
the hub and core prints loose allows the coupling to be adapted 
to several diameters of shaft. This requirement occurs when 




Fig. 296. One-Half of Complete Flange Coupling 



172 



PATTERN MAKING 



Loose 
hub 




^f^ Cope Print 



Fig. 297. 



an increase or reduction of the diameter of a line of sliafting 
is made. 

Equipment for Machine Use, It is now desired to construct 
a molding machine, Fig. 298, with as little expense and delay as 
possible, whereby a machine molder may produce the easting. 
The principle used will be a hand roll over stripping-plate process. 
Figs. 298, 299, 300, and 301 are used to show the equipment 
requirements, and like letters represent like parts in all figures. 

Fig. 299 illustrates a sec- 
Nowel Prinf>UiaMWe tion of the completed ma- 

chine, on a center line 
through the €ask pins ii. 
Pattern, The only al- 
teration in the pattern for 
the flange and web of the 
couplings will be in the 
thickness of the web c, 
which must be thick enough 
to reach through the strip- 
ping plate b and is to be 
fastened to the draw plate a with three or four flat-head wooden 
screws. Follow the process already established when making the 
web, flange, and hub. The hub shall be made loose, and the 
core prints also, unless the diameter of the cored hole is standard 
to the hub, when it will be best to make the nowel core print a 
part of the hub. 

Stripping Plate, The stripping plate, Figs. 298 and 299, at b, 
and the core plate, Fig. 298, at n, are alike in size. The width 
should not be greater than the flask, Fig. 301, so that what sand 
falls over the outside of the flask should fall to the floor. The 
length, however, should extend beyond the flask far enough to include 
the flask pins i. The stock for these plates/is to be about If inches 
thick, and had better be made of narrow strips of stock glued 
together, with the heart side reversed on alternate pieces so as to 
prevent warping. The stock should be dry, and have a heavy spline 
glued in each end, as shown. 

Draiv Plate. The draw plate should be about the same length 
and thickness as the stripping plate. The width may be somewhat 



Section of Hand-Molded Pattern — Loose 
Hub and Prints 



PATTERN MAKING 



173 



less than the stripping plate, but not less thaii the diameter of the 
pattern, and not so as to cause the outfit to tip during the ramming 
of the mold. This plate is not splined at the ends, but heavy 
cleats are glued and screwed in place, as shown in Figs. 298 and 




Fig. 298. Simple Form of Molding Machine which Embodies Stripping-PIate 
and Turn-Over Ideaa 



299, first cutting out stock at the ends of the plate to form hand 
holes. 

Assembling. On both the stripping and draw plates lay out 
a center line for the location of the pattern and the flask pins, and 



174 



PATTERN MAKING 



also a checking line parallel to this center line, spaced off exactly 

one-half of the diameter of the flange of the pattern,—-. After estab- 

lishing the location of the pattern and flask pins, the 1-inch hole 
can be bored in the cope plate, and the hole in the stripping plate 
for the flange c can be carefully sawed with a jig saw or keyhole 
saw. This hole should be fitted over the pattern by blue-chalking 
the outside of the flange and trimming the stripping-plate stock 
where the chalk shows. This hole will have to be about -^ inch 
larger in diameter than the pattern so there will not be any binding 
when the pattern is drawn through the stripping plate. The stock 




Fig. 209. Section through Center ot Nowel Mold Machine 



is bound to swell to some extent, but a small amount of sand getting 
between pattern and stripping plate will grind out the stock, so there 
will be little trouble from this source. 

flask Connection, The flask pins i are to be made of cast iron 
or machine steel. The diameter of the pin is to be about J inch, 
and the flange about 2 inches in diameter and | inch thick. The 
diameter of the pin should be parallel, to a height of about ^ inch, 
and slightly tapered above this point to a total height of about 
\j inches. The flange should be drilled and counterbored for three 
flat-head wooden screws, or, better yet, tapped for three flat-head 
stove bolts, which will be passed up through the plate stock. Coun- 
terbore holes in the stripping plate and cope plate, for the flanges 
of the-se flask pins, beuig veiy careful to center these holes accurately. 



PATTERN MAKING 



175 



Fasten the pattern to the draw plate and place the stripping 
plate in position. Test the dimensions gg with inside calipers, 
as shown in Fig. 299 also check the dimension h with the flask- 




Fig. 300. Jig for Locating Centers of Flask Pins on Machines 

pin jig shown in Fig. 300. This jig is made of flat steel stock, and 
the holes are drilled with the same jig which is used for drilling 
the holes in the flask, Fig. 301. Test the distance from the checking 
line to the flask pins with hermaphrodite calipers, as shown in 



fiowel 
r/ash 



Closing Pin 




SECTIOti 
THRU LUG 

Fig. 301. Sketches of Cast-iron Flask Showing Closing Pins 

Fig. 298. Test the location of the cope core print in the same 
manner. The flask pins can be adjusted by loosening the screws 
and driving a wedge between the pin and the plate stock so as to 
force the pin into the correct location. The alignment of the pattern 



176 PATTERN MAKING 

and the flask pins should be such that the mold can be closed with 
the cope either way around; however, the location of the sprue 
will determine this. 

Gate. The pattern for the gate /r, Fig. 298, is crescent 
shaped and is nailed to the stripping plate. The pattern maker 
had better consult the experienced molder for the dimensions of 
this gate. A small hole should be drilled in the cope plate 
at 0, Fig. 298, so as to locate the sprue opposite the center of the 
gate pattern. 

Identification Marks. Pattern numbers, size of coupling, or 
other means of identification should be marked on each end of the 
stripping plate. Iii this location they can readily be seen when 
the patterns are on the storage rack. Do not place these marks 
on the ends of the draw plate, as the pattern is rapped by striking 
the ends of the draw plate before the pattern is drawTi. Closing 
pins, Fig. 301, are used while closing the mold, and these are then 
to be removed. 

Parallel Drawing Device 

Typical Deep=Draw Work. WTien the pattern, like the spur 
gear illustrated in Fig. 302, has considerable depth of draw d, there 
is liability of one end of the draw board being lifted ahead of the 
other, which will cant the pattern and loosen the sand between 
the teeth of the pattern, making it impossible to obtain a perfect 
casting. With the parallel device shown, the draw will be per- 
fectly true and very delicate molds can be made. It is not intended 
that patterns mounted in this manner should compete for accuracy 
w^th an all metal st ripping-plate machine, but its ease of handling 
and roll over suggests its use for many castings frequently mounted 
on the stripping-plate machine. 

Spur-Gear Pattern. The gear pattern is to be made of mahogany 
— the stock glued to obtain the required dimensions, and having 
the grain parallel to the axis. Band saw nearly to diameter, bore 
a 1-inch hole through it at the center, and turn on an arbor. In 
the assembly. Fig. 303, the length d shall be the sum of the face 
of the gear and thickness of the stripping plate. Have the teeth 
cut in a gear cutter. This is the same machine used to cut the teeth 
of metal gears, and conmaercial gear cutters generally have one 



PATTERN MAKING 



177 



of their machines adapted to this work. The spindle upon which 
the milling cutter is mounted is run at a speed that will insure 



rHorn sprue 




Fig. 302. Draw Plate for Spur-Gear Casting 




Fig. 303. Elevation of Spur Gear and Draw Plate 

smooth work, and a single cutter, called a fly cutter, is fitted to the 
spindle in place of the milling cutter. 



178 



PATTERN MAKING 



Stripping Plate and Draw Board, The stock for the stripping 
plate and draw board may be prepared while waiting for the gear 
pattern. Thesp are to be made of glued stock, splined and cleated 
the same as in connection with the flange coupling. While not 
shown, a cope plate shall be made which will be similar to the cope 
plate for the flange coupling illustrated in Fig, 298. This should 
be made along with the drag machine. At A, in Fig. 304, bore 
M-iuch holes through both the stripping plate and the draw board. 
Mount the stripping plate on a faceplate using care to have 
the center of the stripping plate and lathe concentric, and turn 




Fig. 304. Section Shomng Loose Nowel Core Print 

a hole with a diameter equal to the bottom of the gear teeth; 
also chuck a recess for the brass wear plate if one is used. 
Machines have been made without this brass plate, but better 
results can be obtained with it. It may be cut from sheet brass 
or a casting may be used. 

Metal Parts, If a brass plate is used on the stripping plate^ 
the projections which extend into the tooth space should be care- 
fully filed' to pass over the pattern easily. Mark the strippmg 
plate to this form and jig-saw it. After fastening the brass plate 
with several flat-head wooden screws, the hole is to be trimmed so 
that the pattern will not biud. 

The metal pattern maker or a machinist can furnish the metal 
parts, or if necessary tools are at hand, the pattern maker will not 
find much difficulty in making them. The flask pins, however, 



PATTERN MAKING 



179 



should be machlne'^urned all over and made duplicate, for, in case 
of breaking, the labor of replacing will be very much lessened if 
the pin can be replaced without changing the alignment of the 
pattern. 

Parallel Device. For the side arms of the parallel device, 
Fig. 306, the stock should be black iron, 1} inches long by I inch, 
and the length 1 or 2 inches less than the length of the draw board* 
Make a full-size layout of the motion of the parallel device aa 




Fig. 305. Layout for Side Arm of Parallftl Motion Device 

illustrated in Fig. 305. The radius r and the dimension s must be 
the same. 

Side Arms, From points a, e, and q, project vertical lines 
aj and qb. Make all straight lines with a knife point. With / 
for a center, scribe arc blop with radius Jc, which is the sum of r 
and s. Locate above / the point g with dimension w, and point j 
with dimension cZ-f-| inch. Dimension w is as in Fig.. 303, and the 
I inch added to <i is to insure drawing the pattern clear of the mold. 
Point i is to be located approximately f of c? above g. These points 
g, i, and j are to be projected on vertical line I n. Through the 
intersections of these horizontal projections with arc hpot o and p, 
lay out radial lines centering at/, and extend these lines tb intersect 
line In at m and n. 



180 



PATTERN MAKING 



Project points 6, c, and dto the plan of the side arm, and transfer 
dimensions t and u to intersect these lines, giving three points 
upon which to lay out a curve which will be the center line of the 
slot. Lay out these centers on one piece of stock, and, clamping 
the four pieces together, drill out at one time. The hole at e will 
be for a ^^inch rivet, and the holes drilled to form the slot at q 
will be the same diameter as a No. 16 screw. These screws over 
which the slot slides should be round-head, No. 16 wire, and about 
2| inches long. 

Cross Rods. The rods v, Fig. 306, which connect the opposite 
sides are to be f inch in diameter, and the ends are to be filed to a 




Fig. 306. Details of Parallel Motion Device 

square, and a J|-inch hole drilled at a, Fig. 305, will be filed square 
to fit these squared ends. Two side arms are to be riveted together 
at e, Fig. 305, reversing the slots, as shown in Fig. 306, and the 
|-inch rods riveted to one pair of side arms; the other pair Will be 
riveted after passing the rods through the stripping plate and 
draw board. 

Short pieces of flat iron, of the same section as the side arms, 
are furnished with a f-inch hole at center, and a hole near each 
end countersunk for a flat-head wood screw, as illustrated in Fig. 306. 

Assembly. Assemble the device on the wooden plates. Fasten 
the bearing plates in the correct location, and, having the draw 



PATTERN MAKING 



181 



board and stripping plate held tightly tbgether, insert the round- 
head screws in the slots. Try the lift of the draw board, Fig. 307, 
and, if not equal to d+\ inch, lengthen the slot to obtain this dimen- 
sion. All parts should have three or four coats of a shellac finish 
betoxe assembly* Fasten the pattern to the draw board with three 




Fig. 307. Draw Plate Turned over and Pattern Drawn; Flask and Bottom 

Board Also Shown. A further Lift of Drawboard Removes 

Machine from Mold 

or four wooden screws. The flask pins should be located to fit the 
flask-pin gage, as illustrated in Fig. 303. The mold board for the 
cope mold should have a 1-inch hole at its center to receive the 
dc'vel of the cope core print and a hole for marking the location 
of the sprue. 

Horn-Sprue Gate, The horn-sprue gate should be made of 
hard wood or metal and should be furnished by the pattern maker. ^ 
The dimensions should be suggested by the molder, and the dimen- 



182 



PATTERN MAKING 



sions of the flask used should be selected so as to provide room 
for this gate. The gate should be roimd in section, and gradually 
taper from the parting of the flask to the pattern. The inner and 
outer sides should be true circles so that it can be drawn out end- 
wise. A steel pin is to be fitted in each end of the gate pattern and 
a hole drilled in the stripping plate and pattern to locate the gate. 
The sprue in the cope mold must be located so as to match the 
gate in the drag. 

STRIPPINQ-PLATE HAND-RAMMED MOLDING MACHINE 
Hand-Molding Conditions. Before taking up the design and 
construction of the parts required to adapt the patterns to machine 



I J 



D 



O 



^' 






Hord Wood Bearing 



l! il ! liJlii!l..p- A^ 



Holder Frame 




Section S-S 



Fig. 308. Working Drawing of Holder Frame that Requires Side Draw 

molding, the conditions presented by the hand-molded patterns 
may be briefly considered. The working drawing, without dimen- 



PATTERN MAKING 



183 



sions, of a holder frame is illustrated in Fig. 308; and in Fig. 309 
is a view of the iron-gated patterns. The cover is designed to pass 




Fig. 309. Original Gated Patterns, Showing First Attempt to Increase Produc- 
tion. They Require Dry-Sand Core for Each Casting. With Machine- 
Mounted Patterns, Entire Mold la Alade in Green Sand 




Fig. 310. Nowel or Drag Stripping-PIate Hand-Rammed 
Molding Machine 

endwise onto the holder frame, as indicated in Fig. 308, the bevel 
on the inside of the lugs o being molded with a dry-sand core, and 
the round recesses in the holder also being molded with a dry-sand 



184 



PATTERN MAKING 



core. The least imperfection to these dry-sand cores means that 
considerable fitting has to be done to get the parts assembled,^ With 




.Fig. 311. Drag Machine with Pattern in Position to Make Mold 
1^ 




^^Dra*y^Plate 



Fig. 312. End Elevation of Pattern Equipment for ReJd Hand-Rammed 
Stripping-Plate Machine 



PATTERN MAKING 



185 



the machine-molded castings, the castings and the hard-wood 
bearings are literally thrown together. 

Molding Machine, In Fig. 310 is illustrated the drag machine, 
and in Fig. 311, the machine with the pattern in position for mold- 
ing. An end view of the stripping plate, draw plate, and assembled 
mechanism of the drag machine is illustrated in Fig. 312, and Fig. 313 
is a section through the center of one pattern. This machine is 
fitted to make four molds which are all gated to one sprue. The 
mechanism unit is duplicated for each pattern. 

The proposition with this drag machine is to draw the pattern 
at an angle of about 30 degrees from the vertical, and therefor© 







Fig. 313. Section Elevation through One Pattern; Dotted Lines Show Position of 
Parts with Pattern Drawn 



the pattern cannot be bolted directly to the draw plate a. To 
obtain space beneath the stripping plate to install the mechanism 
spacers are interposed between the top of the machine frame and- 
the underside of the stripping plate, as shown at m and m. In 
Fig. 313 the pattern is illustrated in its raised position, and the dotted 
lines illustrate the position of the draw plate and levers when the 
pattern has been drawn. 

Stripping Plate. A perspective sketch of the stripping plate 
is illustrated in Fig. 314, part of the casting having been broken 
away to illustrate the position of the holes through which the pattern 
is drawn, and Fig. 315 is a sketch of the pattern for the stripping 



186 



PATTERN MAKING 



plate. Small blocks Oi of cast iron or steel are to be fastened at 
each end of the depression after the machine planing is completed. 




in tAe ncntei moid. 



Fig. 314. Diagram of Stripping Plate. One Bod Brokea to Show Holes through 
Which Pattern Is Drawn — 



Cope core print. 

The pattern pa.ris on 
this line 




Fig. 315, Pattern for Stripping Plate"" 



Plate Pattern, The plate is made of narrow strips of stock, 
glued so as to reverse the heart side of adjoining pieces. It will 
not be necessary' to spline these patterns, for only one casting is 



PATTERN MAKING 



187 



usually required and the pattern is generally molded as soon as it 
is completed. 

Molding, What is to be the top of the casting is molded in 
the drag mold so as to be sure of obtaining a clear surface. Most 




* Fig. 316. Core Box for Core, Fig. 317 

of the causes of imperfections in castings rise to the top of the mold 

while the metal is being poured, and thus, if there are gas or dirt 

blowholes in a casting, 

they will be found in 

the cope side of the 

casting. The casting is 

parted where shown, 

and the cope part of 

the pattern should be 

located on the drag with 

two dowel pins. 

Coring, The core 
for the cope shall be 
made in a skeleton core 
box. No sketch is shown 
of this core box, but its 
construction would be 
similar to the core box for the part g, illustrated in Fig. 318. 
Fig. 316 illustrates the dry-sand core used in the drag mold, and 
Fig. 317 the core box for the core. This sketch shows the box 




Print 



Fig. 317, Dry-Sand Core for Making Holes in Stripping 
Plates through Which Pattern Is Drawn 



188 



PATTERN MAKING 



partly assembled and cut away so as to illustrate the construction. 
When it is certain that the parts are accurately cut to the required 
dimensions, they should be nailed and glued. One^end is fastened 
to one side of the box, and the opposite end to the other side. No 
dowel pins are required as the shoulder holds the sides in alignment* 
Produce a slight draft to the parts forming the holes p, and a filing 
£nish of about ^ inch should be allowed on the sides of these holes. 




45/re?eft»7 Cor^-hox 
Fig. 318. Casting Pattern and Core Box for Part g. Pig. 3i2 

Brackets. The sketches of the parts g and k, Figs. 318 and 319, 
should readily explain themselves. A dry-sand core is used to mold 
the part g, a sketch of the pattern and skeleton core box being given 
in Fig. 318. This was deemed necessary owing to the length of the 
dimension gi. At best, the pattern would be quite fragile. The 
pattern for the part k, Fig. 319, should be made without a 
core print. 

The master pattern and core box for the part o, Fig. 320, which 
is the pattern for the drag machine, are illustrated in Figs. 321 
and 322. When making the wood pattern, double shrink should 
be allowed, and a filing finish of not over ^ inch should be added 



PATTERN MAKING 



189 




to all surfaces. The sketch of the core box shows a construction 
similar to that of those described in Part II, Pattern Making. 
The round hole at the lower end of the 
casting is to be finished to slide easily over 
the stool. 

Use of Stool. Whenever it becomes 
necessary to strip an internal surface of a 
pattern, as illustrated in the socket or hous- 
ing for the hardwood bearing used in the 
holder frame, Fig. 308, some means must be 
provided to support the molding sand, and 
this part of the equipment is called a stool. Illustrations of the 
stool for this pattern are shown in Figs. 312, 313, 323, and 324. 

The top surface of these stools are made to the form of the 
hole or recess which it is desired to strip, and are usually yoked 
to the underside of the stripping plate. In this case, a projection 
cast to the underside of the stripping plate serves as a support 
for the stools. They are to be made of machine steel, and, together. 



Fmis^hed to diameter of stool oil i.- 



Fig. 319. Sketch of Cast-iron 
Part k. Fig. 312 





Fig. 320. Casting for 
Pattern c, Fig. 312 



Fig. 321. Master Pattern for Part c 



with the levers and links. Fig. 325, do not require a pattern, but 
accurate sketches or drawings, preferably full size, should be made 
by the pattern maker for these parts for the use of the metal- 
pattern maker. 

Owing to the expense of the stripping plate equipment, this 
method should not be employed unless some feature of the casting 
prohibits the use of the simpler methods. 



190 



PATTERN MAKING 



Finis/i to dia,. t 



Use of Match Plate. A large part of this pattern which will 
be molded in the cope, has an abundance of draft, and as the other 

parts are not over i inch thick, 
a slight draft can be allowed to 
these parts, and a draft of fully 
1 inch per foot can be allowed 
in the square hole. Therefore, it 
will be perfectly practical to mold 



5hoolder 





Fig. 322. Core Box for Master Pattern, 
Fig. 321 



Fig. 323. Sketch of Stool e, Fig. 312 



this side of the casting on a match plate, Fig. 326, and, while a 
pneumatic vibrator is shown, possibly it may not be necessary. 

The vibrator is operated 
while the plate is being 
drawn or lifted from the 
cope mold, causing a 
very rapid vibration to 
the pattern and plate, 
and greatly facilitating 
the drawing of intricate 
patterns. 



^ 











*w* 




♦— y-« 


T 


-- 




- 


i 


KoOixn^ Steei Stools 
6 HcqiAne^ 








'l 



Fig. 324. Drawing of Steel Stool, Fig. 323 



6 



/I'rr 



-\— 



-I^ 









Fig. 325. 



E9 — ^CT)— - (i-/-ij 



4 Required 



Machine Steel Lever and Linics 



The iron plate should be finished on both sides, as the parting 
must match that made on the drag machine. The part <7i is a 



PATTERN MAKING 



101 



separate casting, and this must be machined to fit the recess q in the 
stripping plate. 

'SfeelPin for 

J^fing Sprue 





Fig. 326. Match Plate for Cope Mold with Vibrator Att^bed 

Fig. 327 illustrates the master pattern. Double shrink and a 
file finish must be allowed. 

Gate. A pattern for the gate, Fig. 328, must be furnished, and 
is usually made of cast brass. The location of feedmg into the 
mold and its dimension 
should be suggested by the 
molder. It never should 
feed against. a green-sand 
core, as the core would 
very likely be washed 
away. 

The parts qu Cl, and the ^ig. 327. Master Pattern 

gate pattern are attached to the plate with flat-head machine screws. 

Alignment Of course the alignment of the patterns on the 
cope and drag machines 
must be very exact to 
produce perfect castings, 
but this is the work of 
the metal-pattern maker. 
To avoid errors, there 
should always be a 
trial casting made and 
accepted before the outfit 
is passed to the foundry ready for the commercial product. 

Use of Roll Back. Figs. 329 and 330 are illustrations of the 
cope and drag machines for molding the cover. The distinctive 




Fig. 328. Master Pattern for Gate 



192 



PATTERN MAKING 



feature of the pattern for the cover is the roll-back method of drawing 
the pattern on the cope machine, which is illustrated in section 




Fig. 329. Cope and Drag Machines for Molding Cover 

in Fig. 331. The pattern c is shown in position for molding and 
also after being drawn. The patterns cc are assembled on the 
pin P and mounted in the forged yoke or hanger H, which is bolted 




Fig. 330. Cope and Drag Machines with Pattern in Position for Molding 

to the underside of the stripping plate B, The heads of the set 
screws which are illustrated on the draw plate A press against the 



PATTERN MAKING 



193 



patterns at E, raising the patterns to the desired height. Upon 
lowering the draw plate, this allows the coil springs which are 




JSffction ;5-5 Bottom Dratvn 



Fig. 331. Sections Showing Mechanism of Machine with Pattern in Place for Molding and 
-with Pattern Drawn or Rolled Back 



interposed between the pattern members and the stripping plate to 
force the pattern out of the mold with an oblique or roll-back motion. 

Co'pe Pattern. The master 
pattern illustrated in Fig. 332 
is constructed of three pieces 
of stock, nailed and glued 
together. As in the case of 
all master patterns, use the 
double-shrink rule and also 
add a filing finish allowance of 
about ^ inch to such surfaces 
as form the pattern. Two 
castings are required from this master pattern for each pattern 
mounted on the machine. Fig. 333 illustrates the forged yoke H,, 




fig. 332. Master Pattern 



194^ 



PATTERN MAKING 



Cope Stripping Plate, A perspective view of the* stripping plate 
for the cope machine is illustrated in Fig. 334. The angle and 

dimensions of the recess J 
in the top are determined 
from the original drawing. 
Fig. 308, and from the 
location of the patterns on 
the machine. A finish 
allowance of | inch should 

Fig. 333. Forge Steel or Iron Pattern Hanger ^^ ^^^^ ^^ ^^ ^^p gurfaCC 

of the stripping plate, and cast-iron filler pieces riveted at the 
ends of the recess, as shown at K in Fig, 329. The core box for the 



Core Prints 





Fig. 334. Pattern for Cope Machine Stripping Plate 

cope stripping plate is 
shown in Fig. 335. 

Coring. The core 
prints must be accurately 
placed, and the length 
and width shall be 
slightly smaller than the 
finish sizes to allow for 
the accurate alignment 
of the metal patterns, 
and the cored hole sho uld 
be enlarged below the top surface of the stripping plate. This will 
lighten the labor of fitting these holes to the patterns. The small 




Fig. 335. Core Box for Cope Stripping Pkte 



PATTERN MAKING 



195 



pieces of cast iron or steel, D, Fig. 331, are fastened to the top 
of the stripping plate with flat-head machine screws. 

Drag Stripping Plate. Cope the parting to the top of the pat- 
tern, and a recess to match this is planed in the top of the drag 




Fig. 336. Pattern for Drag Machine Stripping Plat© 

stripping plate, as shown by the dotted line L in Fig. 336. These 
features are also to be seen in Figs 329 and 330. 

Stop-offs should be screwed to the underside of the stripping- 
plate pattern, Fig. 334, as the pattern will be weakened by cutting 




Fig. 337, Core Box for Stripping Plate 

out the stock at J. This recess J can also be made with a dry- 
sand core if it is desired not to weaken the' pattern as suggested 
above. 



196 



PATTERN MAKING 




Core-pHnt 
Fig. 338. Master Pattern for Cover 



Skeleton Core Box, The stripping plate for the drag machine 
is illustrated in Fig. 336, and the core box in Fig. 337. As this 

construction is largely 
repetition, the cuts 
should explain them- 
selves. This skeleton 
core box, however, has 
one new feature; it is 
made in three parts. 
After the core has been 
rammed, the end M is 
drawn, the ends of the 
sides N N holding the core sand so that end M is stripped out of 
the core. ^ The sides can then be removed* 

This illustration clearly shows the method of enlarging the 
lower end of the holes which are cored in the stripping plate. The 

dimension Q shall be the 
height of the core print 
plus f inch, and R shall 
be the total thickness of 
the pattern including the 
core print. 

Drag Pattern. Fig. 
338 shows a perspective 
sketch of the master pat- 
tern for the nowel or drag machine. This pattern must be 
extended to reach through the stripping plate down to the draw 
plate. The feet marked uu shall have a metal-finish allowance 
on the underside, and the weight of the casting can be greatly reduced 




Fig. 339. Pattern for Part F, Fig. 329 




Fig. 340. Master Pjattern of Gate for Holder Frame Cover 

by coring. The core print is to be made first and the other parts 
nailed and glued to it. Use great care to have all parts very accurate, 
keeping the dimensions slightly over size, for the exposed portions 



PATTERN MAKING 



197 



will be file-finished. A simple skeleton core box will do for this core. 

The part Fy Fig. 339, must be finished to the same dimensions 
as the recess J on the cope machine. This piece is screwed to the 
center of the nowel stripping plate, as shown in Fig. 329. 

Gate, The master pattern for the gate is shown in Fig. 340. 
This is a brass casting and is illustrated in Fig. 329 fastened to the 
top of part F, A steel pin, shown at W on the cope machine in 
Fig. 329, locates the sprue. 

Advantages, These machines are in successful operation, the 
improvements over the hand-rammed castings being more castings 
per flask, doing away with the expense of making and setting the 
dry-sand cores, and the uniformity of the castings requiring less 
fitting. 

OREEN-SAND CORING 
Expanding Pattern 

Characteristic Usage. The bearing-cap casting seen in Fig. 341 
was first produced with a hand-molded pattern, using a heel core 



This rectongular^ opening p 




Fig. 341. Sketch of Bearing-Cap Casting 

to mold the square hole in the upright position shown at d. This 
heel core and the setting of it was an expense; there was always an 
unevenness at the surface of the casting caused by the heel of the 
core, which had to be ground smooth. To avoid these objectionable 
features, what is called an expanding pattern may be adopted. 



198 



PATTERN MAKING 



Molding Process. The principal stages of the molding process 
will be considered to give a clear conception of the purposes of the 
several parts. 





Fig. 342. Drag and Cope Machines in Position for Melding 




Fig. 343. Pattern Expanded Ready to Be Drawn through the Stripping Plato 

Drag Mold, Fig. 342 illustrates the cope and drag machine, 
with the patterns in position for molding. As the sand is rammed 
to cover the pattern c, the operator pinches the facing sand into 



PATTERN MAKING 



199 



the hole d with thumb and forefinger. The handle k is then depressed, 
this motion opening or expanding pattern c, as illustrated in Fig. 
343. The mold now has the dimensions required and a green-sand 
core that will form the square hole d. Lowering the draw plate a 




\ 



Fig. S44. Same Machines aa Fig. 342, with Patterns Drawn 



draws the patterns c and Ci through the stripping plate h, and the 
drag mold is completed. The pattern C2 is not drawTX through 
the stripping plate, as enough draft can be given to this part to 
allow the mold to be easily lifted, the flask pins guiding the mold 
until the pattern is clear. 

Fig. 344 illustrates both machines with patterns drawn. 




Fig. 345. End Elevation of Cope Machine 



G)pe Machine. Taking up the construction of the several 
parts, the cope machine will be fitted first. The stripping plate 
will be of standard dimensions, and it will be well to adopt several 
sizes and mount all patterns on these plates so as to avoid the ex* 



200 



PATTERN MAKING 



pense of the numerous sizes of flasks required. The stock stripping- 
plate machines are built with circular and rectangular frames. The 
rectangular frames usually are 12 inches, 14 inches, 16 inches, and 20 

inches square, but it is pos- 
sible to extend the stripping 
and draw plate so that a 12- 
by 14-inch, 12- by 16-inch, 
and 12- by 20-inch flask can 
be used on a 12- by 12-inch 
machine. The machine for 
these patterns has a frame 14 
inches by 14 inches, outside 
dimensions. 

There are to be four pat- 
terns mounted, but, in de- 
scribing the parts, only one 
will be referred to, it being understood that the four patterns 
are connected together and operated by the same motion. A sec- 
tion of the cope-pattern c, and stripping and draw plates are 




fig. 346. Master Pattern for Cope Pattern c. 
Fig. 345 




Fig. 347. Assembled View of Mechanism for Drag Machine 



shown in Fig. 345. Core the holes in the stripping plate by the 
same method as used before. An illustration of the cope master- 
pattern c is shown m Fig. 346. That portion of the pattern above 
the dotted line is above the top of the stripping plate, and should 



PATTERN MAKING 



201 



have a file-finish allowance. The bottom of the bolting flange should 
have a finish allowance of ye inch. 

Drag Machine. The illustration in Fig. 347 is a sketch of the 
assembled parts of the drag machine. The stripping and draw, 
plates are broken away, and the 
frame of the machine is not 
shown. Spacers must be fur- 
nished for this machine, as shown 
at m in Fig. 311. The stripping 
plate is bolted to the outside 
frame and the draw plate to the 
draw frame of the machine. The 
pattern is made of four parts. 
A master pattern for a bronze 
casting of C2 shall be made, and 
this part is to be riveted to the 
stripping plate. Part Ci i^ bolted 
direct to the draw plate. Parts 
cc are supported by the stand g 
which in turn is bolted to the 
draw plate a. The lower end of the right-hand pattern c is con- 
nected by a steel pin to the link ji, not shown; the left-hand c is 
connected to the link 7 by a longer steel pin, which passes through 
a slot in link ji, into a hole in link j. 




Fig. 348. Drag Pattern a. Fig. 347 




Core 
Prints 



Fig. 349. Master Pattern for Part ci, Fig. 348 



Connecting the link J and j\ by the arms I and h to diametrically 
opposite points on the disk k transmits an opposing motion to links 
j and ji, moving the parts ec away from each other, pressing the 



202 



PATTERN MAKING 



Qiold to the form desired, and leaving a green-feand core at d 
to form the square hole in the casting. The drav\' plate can then 




Fig. 350. Core Box for Pattcm, Fig. 349 



be lowered, dra\\ang and stripping the patterns cc and Ci through 
the stripping plate. The links j and ji extend the length of the 




Fig. 351. Nowel End Elevation of Drag Machine 

machine, conecting vnth. the four patterns. The recess o is stripped 
with a stool p, Figs, 351 and 857. These stools and the yoke q, 



PATTERN MAKING 



203 



Figs. 347 and 356, upon which they are attached, are bolted to the 
underside of the stripping plate, as shown in Fig. 351, 

Drag Pattern. The pattern Ci, an illustration of which is shown 
in Fig. 348, will require a finish allowance of ^ inch on the under- 








Fig. 352. Expanding or Crush-Back Motion 



side of the foot, and a file-finish allowance on that part which pro- 
trudes above the stripping plate. The master pattern with its core 




Fig. 353, Master Pattern of Part c, Fig. 352 



box is illustrated in Figs. 349 and 350. As before, the core-print 
stock should be dressed to dimension first, and that part of the pat- 
tern representing iron nailed and glued to it. Use the double- 
shrink rule or allow double shrinkage when making these master 



204 



PATTERN MAKING 



pattenis, and allow planing, turning, and file finish where needed. 

The core box, one side of which is shown removed so as to show 

its construction, is intended to make two cores which when pasted, 

will make tlie core as used in the mold. 

The surface on the pattern enclosed by the dotted line at r 

shall be shellacked to same color as the core prints, as the core 
cuts through at this point, and if it is 
not indicated in this manner the molder 
would be in doubt as to whether the core 
should or should not cut through. Mold- 





Fig. 354. Stand — Support for 
Pattern c. Fig. 353 



Fig. 355. Bracket and Bearing for Operating Device 



ers have been known to file the core to be sure of getting metal 
in a case like this, the reasoning being that if a hole is wanted it 
can be cut out easier than the hole could be filled in, should the 
core be allowed to cut through, The molder should not be left to 
surmise what is wanted. Always mark patterns by some under- 





Fig. 356. Stool Yoke 



Fig. 357 Ma-ster Pat- 
tern oC Stool 



stood method so that there will Ibe no need of verbal instructions 
to the molder. 

Expanding Motion. Fig. 351 is an end view of the nowel or 
drag mounting, and in Fig. 352 the layout of the patterns c c is illus- 
trated. IMake a full-size layout of this motion; the dimension v 
shall be such that when the pattern c is drawn it will not strike and 




PATTERN MAKING 205 

break down the green-sand core d. This dimension v-^x must 

be slightly less than —, w being the dimension of the width of the 
it 

pattern. 

Fig. 353 illustrates the master pattern of the part c. Two 

castings from this pattern can be fitted together as shown in 

Fig. 352. The length 

from the center to the 

lower end is optional, 

but the top of the strips 

ping plate should be 

kept as low £3 possible. 

nyy ^ ^ ■ Fig. 358. Master Pattern of Gate 

The operatcr can work 

easier and meld l!ic pattern quicker if he does not have to 

shovel the sand too Li^ii. 

The parts g and n, illustrated in Figs. 354 and 355, and their 
object, as shown in Fig. 347, should explain all that is necessary. 
Their dimensions are fixed by the dimension requirements of the 
commercial casting. 

Fig. 356 illustrates the stool yoke q. The parts y extend into the 
pattern Ci, as shown in Fig. 35 1-, and the stool p is attached as shown. 
The top of this stool, a sketch of which is shown in Fig. 357, is fitted 
to the recess o in the pattern Ci, shown in Fig. 348, and is used 
to prevent the sand in this recess from following the pattern 
when the pattern is drawn; in other words, it acts in just the 
same manner as the stripping plate does with the outside of the 
pattern. 

The sheet-metal cover over the expanding-motion device, 
shown, in Fig. 342, is intended to prevent the molding sand getting 
into the bearings and causing excessive wear. The handle h will 
be made of machine steel, threaded on the machine end, and screwed 
into the periphery of the disk h, as shown in Fig. 347. This handle 
should be designed to be easily removed, while storing the machine, 
to prevent breakage. 

Gate. Fig. 358 illustrates the master pattern for the gate 
pattern. This will be a bronze casting and is fastened to the cope 
machine. A steel pin should also be fitted to this gate pattern 
to locate the sprue. 



206 



PATTERN MAKING 



Double-Draw Stripping-PIate Machine 

Typical Feature. The feature of this arrangement used for 
molding the jaw clutch, Fig. 359, is that the pattern is used as a 
stripping plate for the hub and the clutch jaws. It was specified 
that there was to be no draft on these parts, and that the corners 
betw^een the disk g and the jaws / must be very sharp and clean. 
Construction, In Fig. 360 the right-hand section is taken 
midway between two jaws, and the left-hand section through the 
center of one of the jaws. 

Stripping Plate. The stripping plate is constructed to the same 
dimensions as used for the other castings. As described, it is fitted 
for one casting mounted on a square frame machine, but a round 

machine will do as well, 
or two patterns can be 
fitted by extending the 
plates a and 6. The pat- 
tern hole in the stripping 
plate is cored and ma- 
chined to dimension, and 
the underside must be 
finished parallel to the top 
side for a space of about 
i inch outside the hole. 

Disk Pattern. A 
shoulder is made on the 
outside of the disk pat- 
tern g to act as a stop to prevent the pattern from being raised 
above the height desired. The dimension i should be such that 
pattern g will be Uteld rigidly between the stripping plate and- the 
draw plate when the latter is in a raised position. 

Fig. 361 illustrates the master pattern for disk pattern g. The 
holes through which the jaw patterns / pass are designed to be 
made by the metal-pattern maker, the stock not being over J inch 
thick. Allow a finish of -^ inch to | inch on all. outside surfaces, 
but the inside is not to be machined. 

Hub Pattern, The pattern for the hub e can be made of a 
casting or of machine steel, and is bolted to the draw plate, as 
shown in section in Fig. 360... 




Fig. 359 



Casting Molded on Double-Draw Strippmg- 
Plate Machine 



PATTERN MAKING 



207 



Jaw Pattern. Six castings will be required of the jaw pattern/. 
A sketch of the master pattern is shown in Fig. 362. A file finish 
is to be allowed to the upper end and a planing or milling finish 
of r^ i^ch allowed to the underside of the foot. These parts are 
tobe bolted to the draw plate. 

Draw Rods. There are to be three bosses on the underside of 
the disk, illustrated at j in Fig. 361, and into tapped holes in these 




Fig. 360. Section of Pattern, Stripping Plate, and Draw Plate 
for Casting, Fig. 359 

bosses J-inch soft steel rods are fitted, as shown at k in Fig. 360. 
These bosses are located so as to come between every other jaw 
pattern, and holes are to be drilled in the draw plate through which 
the steel draw rods k will pass. 

Open springs are placed on the draw rods between the pattern 
g and the draw plate, and they should be capable of holding the 
pattern g in place until the hub ^ with the jaws/ have been stripped, 
when the imderside of the draw plate, upon striking the nuts on the 



208 



PATTERN MAKING 



draw rods, draws the pattern g through the stripping plate. In 
raising the pattern the operation is reversed, the draw plate forcing 





Fie. 361. Master Pattern of Disk 



Fig. 3G2. Master Pattern of 
Clutch Jaws 



the pattern g into the correct position at the end of its upward 
motion. 

Cope Plate. The cope mold is made on a cope plate having 
only the cope core print, the locating pin for the sprue, and the 
flask pins. 

Gate. The gate pattern will be similar ta that used far the 
flange coupling, as is seen in Fig. 298. 

Qreen=Sand Core Box 

Suitability. Such castings as short lengths of pipe, and elbow 
and T-pipe fittings of reasonable diameter lend themselves readily 
to this method of molding. It would not be economy to equip 
for this method if a very few castings are required, or w^here the 
requirements \tould suggest the costly equipment for cashing pipes 
on end. Like ^ther methods of molding, it has its scope, and the 
pattern maker should not attempt to design an equipment for this 
work without first consulting with the master molder. 

Pipe Pattern. The casting considered will be a short length 
of cast-iron pipe, 72 inches long, 6 inches inside diameter, and 
flanged at one end. The construction of the pattern wull not be 
considered, as it is a parted pattern with a detachable flange similar 
to that considered before. In fact there is no difference in the pat- 
tern used "with a dry-sand or with a green-sand core. 



PATTERN MAKING 



209 



Green=Sand Core. Fig. 363 illustrates the iron core box, 
the halves being liinged together as shown at a. The arbor, Fig. 371, 



tfov^cl or 




Fig. 363. Iron Core Box for Green-Sand Core 




Fig. 364. Core Box Closed 



is placed in the drag half, the ends extending through the notched 
ends of the core box. Green sand is rammed in drag and cope and 
struck off level with the top of each half. The core box is closed 



210 



PATTERN MAKING 



by lifting on all four handles like closing a book, print upward, 
then rolling over into position shown in ¥ig. 3G4. Tlie upper half 




Fig, 365. Pipe Core Set in Mold 

of the core box can now be retiu-ned to its first position, leaving the 
cope half of the core resting on the drag itself. The complete 




Fig. 366. Start of Core Box 



core can then be drawn from the core box — lifting it by the arbor 
extensions — and placed directly in the mold. The flask ends should 
be notched to receive the arbor extensions, as illustrated in Fig. 365. 



PATTERN MAKING 



211 



Core-Box Construction. Several methods of constructing the 
master pattern for the core box may be utilized. As only two 
castings are required-=^ne for each half of the core box — the quickest 




Fig. 367 Pattern Assembled on False Cope Ready for Ramming Cope Mold 

method of constructing the pattern should be used, provided the 
results are accurate. A nailed and glued pattern using a green-sand 
core for molding the inside would produce the smoothest casting, 
Fig. 366. The pattern, however, would be very fragile, and a form 




Fig. 368. Wooden Form 

should be made to fit the inside to hold it in shape while ramming 
the drag mold. 

Use of Form, The construction considered will be to furnish 
the molder with separate flanges and lagging, and assemble the parts 
on a wooden form, Fig. 367, or a dry-sand core can often be used in 
place of the wooden form. 



212 



PATTERN MAKING 



The form, Fig. 368, is constructed of thin strips of wood nailed 
to several semicircular heads shown at h; the length to be the 
inside length of the core box. The strips of lagging should be about 
f inch thick; the edges need not be fitted together, but the diameter 
must be of the dimension required. The pieces h should be made 
I inch over the half circle; that is, the center of the circle is | inch in 
from the edge, as shown at i in Fig. 369. This \ inch is for a metal 
finish allowance on the face of each half, as the core box must close 




Fig. 369. Ends, Flanges, and Hinge Lugs 



accurately its entire length. Part h is the end flange, and c is a lug, 
shoTVTi in Figs. 367 and 369. The space between h and c is wide 
enough to allow the part d to turn easily. This form of hinge, 
having a double shear to the steel pin a, is very strong and much 
better than if only one lug were used on each half of the core box. 
The part e is the transverse flange, while / and d form the end of 
the cope half. Lagging is to be provided which should be about 
\ inch thick and | inch wide. This is shown in Fig. 367 at k, and 



PATTERN MAKING 



213 



the part g, Figs. 365 and 367, is nailed to one of these strips of lagging, 
83 shown in Fig. 369. 

Fig. 367 illustrates the several parts of the pattern assembled 
on what is called a false cope. This cope flask is rammed and 
struck off level with the joint; the form j is placed in position; the 
flanges I and the lagging k are laid upon this form. The ends b 
and the lugs c are located, and that part m of the hinge lugs is bedded 
into the false cope, Fig. 367. The drag mold can now be rammed 
and turned over, the false cope removed and the form j removed. 
The cope mold is now made and the pattern can be drawn. 




Pattern qf Handle 



Fig. 370. Core Box for Cast-Iron Handle 



If it should be desired to mold the inside of the core-box casting 
with a dry-sand core, the form j may be omitted and the pattern 
parts assembled directly on this core. 

Handles, Handles should be cast on each half of the box, 
as illustrate4 in Figs. 363 and 364. These handles are molded in 
a dry-sand core and rammed in the mold, as shown at n in Fig. 367. 
The core box for this handle is illustrated in Fig. 370. The length 
of the handle should be about 4| inches, the diameter about 1} 
inches, and the diameter of the hole | inch. Allow about 1 inch of 
core sand on each side of \he handle pattern and a draft of fully 
\ inch on each side. The height or depth will be 5J inches for a 
handle of these dimensions, making the top end of the core print 



214 PATTERN MAKING 

flush with the top of the core box. A cylindrical stock core { inch 
in diameter is pasted into this core, so as to cast a hollow handle. 
Arbor, The skeleton frame used for reinforcing the drag half 
of the core is an iron casting. This is illustrated in Fig. 371. The 
pattern consists of a rectangular arbor r and of several patterns 
for the flanges s. These flanges should be notched to fit over the 
arbor, but need not be attached in any other way, the molder placing 
them in the position required; his judgment of the spacing would 
naturally be better than the pattern maker's. The end flanges 
should be placed at the extreme end of the core. The outside 
diameter a would be about f inch less than the outside diameter 




Fig. 371. Cast-iron Arbor 

of the core, and the thickness about I inch. The outside circiJar 
edges should be chamfered to a thin edge, so as to prevent soft 
ramming under the flanges. The width q should be J inch less 
than the half circle, as it is required to have the sand rammed over 
the top of the arbor. The arbor extensions at each end, however, 
shall be constructed to the center, so that the cope flask will rest 
upon these ends, preventing the arbor and core from lifting when 
the mold is poured. 

HOLLOW ROLL CAST ON STEEL SHAFT 
Split-Pattern Method 

Construction. In the first of the two methods of making the 
cast-iron roll, Fig. 372, to be considered, the steel shaft is placed 



PATTERN MAKING 



215 



in the mold, and, having been spotted with a drill on the portions 
which are in the hubs, is practically bonded with the hubs. 



W////rWW^r^r^/////rWy/^^^^^^ 



c=x 



•^^1 



Tl 

"Sec^l Shaft 



"AOn 



^ 



mm/mm^/<'mmm<'/Mm7?m . 



\i 



Fig. 372. Section- of Cast Roll. Four-Arm Spider at Each End and Steel Shaft Cast In 




Fig. 373. Split Pattern for Cast-Iron Roll 




Fig. 374. Core Box for Making Roll by First Method 

Pattern, The split pattern illustrated in Fig. 373 is constructed 
of wide lagging nailed and glued to heads. The core prints are 
assembled as separate members and fastened to the body of the 



216 PATTERN MAKING 

pattern with wood-screws. The pattern is to be assembled com- 
plete with dowel pins, and the halves are held together by metal 
lathe centers, snob as considered on similar work in Part II, 
Pattern Makmg. 

Core Box. The core box can be made of glued stock, as shown 
in Fig. 374, or a skeleton form of construction can be used if the roll 
is very large. The glued stock illustrated in this figure will probably 
stand up imder the wear and tear of the foundry longer than the 
skeleton construction. Glue the bark side and the heart side of 
adjoining pieces of stock together, and the center pieces may be made 
of narrow stock, thus saving considerable material. 

Cut the inside to a semicircle 
with a core-box plane. At g and i 
the stock is mortised to receive 
the ends of the arm pattern which 
is illustrated in Fig. 375. Two pat- 
terns will be required of this part 
as shown in gg, Fig. 374. The 
dimension e, Fig. 375, should be 
slightly larger than the diameter 
Fvg.375. Part of Core Box, of the stccl shaf t. The part j, Fig. 

^''^- ^^^ 374, which fits into the recesses e 

of the arm pattern is semicircular in section, and forms the recess 
in which the steel shaft is placed. The parts hhhh are patterns 
of the gate. They are not fastened to the arm pattern but are 
bedded in the top face of the core. 

Operation. After ramming the core and bedding in the parts 
k and j, these parts together with the arm pattern are drawn, and 
the space is filled with molding sand. This molding sand prevents 
the core sand from settling when the core has been turned over 
onto its flat side. When pasting the halves together the steel 
shaft is placed in position. 

The mold is cast on end, the sprues being connected to the 
gate h. The metal passes through the upper hub, then on into 
the lower hub and out through the arms, filling the rim; in this 
manner the steel shaft is brought to a very high temperature, 
which fuses the shaft with the hub castings and makes a very 
firm joint. 




PATTERN MAKING 



217 



Stripping-Ring Method 

Characteristics. The following description will show a second 
method for making the cast roll. This arrangement produces clean 
and accurate castings, the machine-iSnish allowance being | inch. 
Fig, 376 illustrates the cheek flask a resting on and keyed to a cast- 
iron mold plate d. The open ring b on top of the flask is a stripping 

ring which holds the molding ^__ . ,_ ,_ .„, , , 

sand in place while the pat- \ I 

tern c is being draw;n. The I j 

pattern in this case has been I 
drawn about 6 inches, the ' , 
power being supplied by a 
crane. Fig. 377 is a section 
view of the arrangement 
shown in Fig. 376. The 
mold plate d should either be 
bolted to a sunken plate to 
hold it down while the pat- 
tern is drawn, or bedded in 
concrete as was done in the 
equipment here shown. 

Roll Pattern, The pat- 
tern is a hollow casting with 
four arms cast at each end, 
and finished all over, and no 
draft is to be allowed. The 
pattern construction will be 
the same as suggested for 
the first method of making 
this roll, but without the 
steel shaft. 

Mold Plate. The mold-plate pattern is shown in Fig. 




Fig. 376. Pattern Being Drawn through 
Stripping Ring 



378. 



This illustration is upside down, and as only one casting is required, 
too much expense should not be put into its construction. The 
upper surface of the casting is to be finished and the recess for the 
dowel in the lower end of the pattern may be made by the machinist. 
Stripping Ring, Fig. 379 illustrates the stripping ring b, A 
pattern for this part is to be furnished allowing finish on the under- 



218 



PATTERN MAKING 



irffing tge 



Po/f 
s^ Pot tern 




foi/ndryf/oor'' 



. 377. Section of Cheek Mold on Mold Plate and Stripping 
Ring in Piace 




Fig. 378. Under Side of Pattern of Mold Plate 



PATTERN MAKING 



219 



side and in the diameter of the hole. This ring should pass easily 
over the roll pattern, and, as soon as the pattern has been drawn, 
this ring is removed and the cheek is complete. 




Pig. 379. Stripping Ring 

Steel Centering Pl'n ^ Dry Sand Core 




Fig. 380. Drag Flask on Mold Plato 




Fig. 381. Cope Mold on Mold Plate 



Flask Construction. Cheeh The pattern for the flask will 
be molded by striking a green-sand core, lagging this to obtain the 



220 



PATTERN MAKING 




Fig. 382. Pattern for Centering Ring 



thickness, and molding the lower flange with a dry-sand core, and 
the upper flange wdth loose segment pattern bedded in. Where 
iron pulley-rim or similar patterns are available, they may be used 

for the flask pattern 
without much expense. 
Allow a metal finish on 
the outside face of the 
flanges, and the inside of 
the flask for a depth of 
about J inch is to be 
turned true, but no fin- 
ish allowance need be 
made on this surface. 
Drag Flask, The drag flask will be of the same diameter as 
the cheek flask, but the depth need be only long enough to include 
the steel shaft. A hub is fitted at its center i, which will be machined 
to fit the finished end of the shaft. A shoulder is turned on the 

shaft, and the upper end of 
this hub is finished so as to 
locate the vertical height of 
the shaft. The drag flask is 
rammed on a cast-iron mold 
plate, as illustrated in Fig. 
380. The flat disk drj^-sand 
core is placed on this plate 
and rammed in, as illustrated 
in Figs. 380 and 384. For 
this core a wooden core box 
should be furnished. 

Cope Flask. The cope 

flask, Fig. 381, is similar to 

the drag flask excepting the 

This ring should be large enough to 

The upper inside edge of this 

A 




Fig. 383. Core Box for Arm Mold 



ring k and the radial bars. 

provide space for the two sprues L 

ring is finished to a bevel to fit the centering ring m, Fig. 384, 

sketch of the pattern for this ring is shown in Fig. 382. 

The mold plate j, illustrated in Fig. 381, can be used for both 
drag and cope molds. 



PATTERN MAKING 



221 



Inside Core. Fig. 383 illustrates the wooden core box for t! 
inside of the mold. The rings n are made of two layers of segment 
glued and screwed together, and the walls of glued lagging firmly 
nailed and glued to the top and bottom rings. It should then be 




11 

I •••••■•>'■.:•• 

1 1-->:^\ 






c; ;;•.-, 







-^kAfi 



ySh^fi cwi^riA<j ring 









.:.•;-•..■:■:••. J 

■*•'•' • -» ^ -Dry .saru/ cares 



Fig. 384. Section of Complete Mold 



i 

'Drq sand cort 



•~Dr3.<j fl<xs,k 



mounted on a faceplate and turned true on the inside and on the 
ends. A very slight draft — about x^ ii^ch — should be allowed on 
the inside, and the height of the box will be 12 inches. The print o, 
hub p, and arm q patterns are fastened to the bottom board r: 



222 PATTERN MAKING 

the ends of the arms centering the outside of the core box with the 
print 0. This print o should be at least y^ inch larger than the 
steel shaft used. Two cores with the arm mold are required, and a 
center core without the arm mold. The length of this core is varied 
to produce rolls of different lengths. A bottom board is furnished 
without the arm and hub patterns, and the length is struck off to 
the height desired. 

Fig. 384 illustrates a section of the complete mold. 

CONCLUSION 

Resume. It may have been noticed that while great accuracy 
has been insisted upon, there have been no difficult problems of 
pattern making required in the adaptation of patterns to the molding 
machine. 

Just as soon as the manufacturing requirements demand 
metal patterns mounted for machine molding, the bench work will 
be simplified. 

The permanence of the master patterns is not a question, as 
they are usually molded soon after being completed, but these 
parts must be very accurately made. 

There is plenty of opportunity for the display of mechanical 
ingenuity, but always consult the foundry experts regarding any 
new venture, for, as stated at the beginning, many patterns have 
been adapted to machine-molding that have proved to be failings 
when tried out in the foundry. 



INDEX 



INDEX 



A PAGE 

Allowances in construction of patterns 52 

drawings, use of. ... 61 

molding practice, general 52 

pulley dimensions, countershaft , 95 

Arbor in green-sand core box ....', 214 

Awls 34 

B 

Bearing-cap expanding pattern 197 

Bearing-cap pattern, use of pattern plate with 166 

Bearing pattern, flanged . 76 

Bevels 27 

Bits 25 

Block plane . 16 

Box cap, pattern for simple journal 55 

Brace 24 

Built-up patterns, construction of 84 

hand wheel 90 

pulley, countershaft . 95 

Pulley, large cored 106 

pulley, sheave , 84 

pulley, standard 100 

Bushing, pattern for 62, 68 

C 

Centrolinead for bevel gear layout 148 

Chisels • . 20 

paring 21 

skew 43 

use of 21 

Chuck pattern, screw 124 

Chucks and faceplates, use of . . , .^ 41 

Circular plane 17 

Clamping process in pattern making 83 

hand screws, use of 83 

pressure regulation 84 

Clamps 35 

Clutch, expanding pattern for jaw 206 

Coloring patterns 75 

Columns, construction of 150 

cores 151 

follow boards 151 

patterns 150 



2 • IXDEX 

Construction of complicated patterns , 

double-draw stripping-plate machine 

expanding pattern for green-sand machine coring. . 

green-saad core box 

hand-molded turbine guide ring 

hollow roll cast on' steel shaft 214 

machine-molding practice 164, 222 

pattern plate, use of 166 

stripping draw-plate machine 171 

stripping-plate for hand-rammed molding nui«-hinc 182 

Construction of simple patterns 67 

built-up patterns 84 

clamping process 83 

columns. 150 

coring, intricate 128 

coring to obviate machining 1 > 

flat-back patterns Ill 

fillets * . 115 

gear wheels 139 

gluing process 81 

one-piece patterns 67 

procedure, conditions of 67 

simpUfied work, examples of 119 

split patterns 70 

Coping-out 

cylinder, simple 

journal cap, perforated 

spoked wheel '. 

Core box, construction of gre^^^ -H 

form, use of 

handles 

Core box, holder-frame 

Core box, methods of fc 

Core box, skeleton 

Core boxes, turbine guide-. 

Core-box-plane ^ 

Core prints, standard 

Coring. 

bottom 

cover 

dry-sand 

89, 105, 106, 116, 121, 123, 124, 126, 132, 137. 151, 15^, ...-. 216 

faceplate for economical machining 

green-sand 57, 67, 84, 197, 206, 

intricate examples of - 

Coupling pattern, flange 171 

Crank pattern, flat-back disk 113 

bosses, construction of 11-1 

counterweight constructivon 115 

disk construction 114 



INDEX 3 

pattern, flat-back disk (continued) page 

:let 115, 

iHi construction 114 

ik pattern, flat-back solid Ill 

ing-off tool 46 

L xider pattern, engine 135 

core boxes 137 

steam chest 136, 138 

Cylinder, pattern for plain hollow 52 

Cylindrical work, patterns for large. . 126 

D 

Dividers . 30 

Double-draw stripping-plate machine . 206 

Doweling split patterns 78 

; Draft in patterns , 62 

template for 63 

variation of 63 

Drafting and designing required, knowledge of 1 

Drawings, use of 61 

allowances for stock 62 

construction conditions 61 

Dry-sand coring 52 

bushing, bearing 68, 81 

chuck, screw 124 

'umns 151 

.mder, engine 137 

indrica] work, large : 126 

"aceplnte, to obviate machining in. 116 

^' ' .182 

216 

221 

121, 123 

, 106 

105 

.e of 89 

turbine case , 59 

turbine guide ring 155 

valve, globe 131 

E 

pai. ,.,, ^/..^ttern, use of 197 

bearing cap, example of 197 

cope machine in 199 

drag machine in 201 

molding process, machine 198 

F 

Faceplate, pattern for cored lathe 116 

Faceplates, use of chucks and 41 



4 INDEX 

PAGE 

Files, wood. 36 

Filing and setting saw teeth 7 

Fillets 115 

putty 116 

usage of 115 

wax and leather 116 

wood 116 

Finish, allowance for 64 

Finishing process, pattern 74 

coloring 75 

final-finishing 76 

sandpapering 75 

shellacking 74 

Flanges, patterns for deep 124 

Flat-back patterns Ill 

Fleam of crosscut saw teeth 9 

Follow boards for thin patterns 151 

G 

Gears, patterns for bevel 140 

arms, construction of 148 

construction, built-up 146 

rim, construction of 147 

teeth, fitting of 148 

Gear-wheel patterns 139 

rim and arm construction 142 

stripping draw-plate machine used with •. 176 

teeth, machine-cut 139 

teeth, patterned 140 

tooth construction 143 

Gluing process in pattern making 81 

application of glue 83 

glue, kinds of 81 

nails, use of 81 

preparation of glue 82 

Gouges N 23 

front-bent 23 

turning 42 

Green-sand core box 208 

arbor with 214 

construction of ...... 211 

pipe pattern, for 208 

suitabiUty 208 

use of 209 

Green-sand coring 67, 197 

bearing cap using expanding pattern 197 

jaw clutch using stripping plate 206 

pipe fittings 208 

ring t\i>e of 57, 84 

Grindstones. . , , , ,38 



INDEX 5 

H PAGE 

Hammer 33 

Hand screws, use of 83 

Hand- wheel patterns. 55, 90 

Solder frame, patterns for machine molding 182 

Hollow plane 18 

Hook of saw teeth 7 

J 

Jack plane 15 

Jointer and hand planing machine 48 

Jointer plane 16 

L 

Lathes and equipment 40 

chisel, skew 43 

chucks and faceplates 41 

cutting-off tool 46 

gouge 42 

scraping tools 44 

Lifting plate for pulley molds, use of 102 

M 

Machine-molding practice . 164 

production, adaptation to 164 

uniformity, increased 165 

Mallet 33 

Marking gage 29 

^Master pattern construction 85 

bearing cap, cope section of special 200 

bearing cap crush back, special 203 

bearing cap, drag section of special 201 

bearing cap gate, special 205 

bearing cap stool, special 204 

core box for pipe, green-sand, 211 

gear wheel 139 

holder frame, cope section of 191 

holder-frame cover, drag section of ' 196 

holder-frame cover, gate for 197 

holder frame, drag section of 188 

holder-frame gate 191 

holder-frame roll back 193 

jaw-clutch disk 206 

jaw-clutch jaws 207 

pulley rim, standard 100 

Match plate in stripping-plate machine, use of 190 

Material, ideal working 2 

Metals, knowledge required of 1 

Molding, general . 52 

coping-out for solid patterns 54 



b INDEX 

Molding, general (continued) page 

cores for hollow castings 52 

dry-sand cores, use of 59 

flask, use of 52 

green-sand ring, use of 57 

loose-piece patterns 59 

split pattern 53 

Molding, machine 164 

stripping draw-plate 172 

st ripping-plate hand-rammed 185 

O 

Oilstones and sHps 36 

One-piece patterns 67 

construction, typical C8 

core box, methods of forming 70 

coring, green-sand 67 

finishing process 74 

shaping pattern 70 

P 

Pattern making 1-222 

construction, comphcated pattern 153-222 

construction, simple pattern 67-152 

requirements, practical 1-66 

Pattern plate, use of 166 

bearing-cap pattern, example of 166 

making pattern plate 168 

molding metal pattern and plate 169 

Pine as pattern material, white 2 

Pipe-connection pattern, T 119 

core box 121 

end fastening 120 

jointing 121 

lathe mounting 120 

Pipe-elbow double pattern 122 

core box 123 

Pipe pattern used with green-sanJ core 208 

Pipe return-bend pattern 123 

Plane, hand 12 

block 16 

circular 17 

construction of iron 12 

core-box type 18 

grinding iron 14 

jack 15 

jointer 16 

rabbet - . 17 

round and hollow 18 

router 20 



INDEX 7 

Plane, hand (continued) page 

scrub ..,,...,. , 17 

smooth ...,, = , = ........ = .....,.,.. 16 

use of, proper 15 

Planing machines 48 

Pliers 35 

Pulley pattern, countershaft , . . . 95 

arms, construction of 95 

construction for special size 95 

coreprints 100 

hub, use of loose 99 

rim construction 97 

Pulley pattern, large cored 106 

arm core 106 

flange core 110 

hub-end core 108 

molding method 106 

molding process • Ill 

rim strike 110 

' Pulley pattern, sheave 57, 84 

coring, dry-sand ring , 89 

coring, green-sand ring 57, 84 

master pattern, mxaldng 85 

Pulley patterns, standard 100 

arms 101 

core prints, standard 105 

hubs 103 

lifting plate, use of 102 

rapping plate 103 

rim master pattern 100 

Q 
Quantity production, patterns for 128 

R 

Rabbet plane 17 

Rapping plate, use of 103 

Requirements, practical pattern-making 1 

allowances in construction 52 

drafting and designing , 1 

metals, knowledge of 1 

tool equipment 7 

woodworking ability 1 

working medium 2 

Roll back in stripping-plate machine, use of 191 

cope pattern , 193 

cope stripping plate 194 

core box, skeleton ^ 196 

coring 194 

drag pattern 196 



8 INDEX 

Roll back in stripping-platc machine, use of (continued) page 

drag stripping plate 195 

gate 197 

Roll cast on shaft, hollow 214 

split-pattern method for 214 

stripping-ring method for 217 

Round plane 18 

Router plane 20 

Rules, measuring 28 

S 

Sandpapering 75 

Saw, back 10 

exercise in using 11 

Saw, band 47 

Saw, circular 46 

Saw, compass 11 

Saw, hand crosscut 8 

filing 9 

setting 10 

teeth, shape of 8 

Saw, hand rip 7 

Saw, scroll 48 

Scraping tools for turning 44 

Screwdriver 34 

Scrub plane 17 

Shaping simple pattern, method of 70 

Sheave-pulley pattern 57, 84 

Shellacking 74 

Shrinkage, allowance for 62 

Shrinkage rule 28 

Smooth plane 16 

Split patterns 88 

hollow roll cast on shaft, for 214 

making, method of - 76 

molding, general 53 

Spokeshave 20 

Square 26 

carpenter's 27 

try- 26 

Stool in stripping-plate machine, use of 189, 205 

Strike for cored-pullej- rim 110 

Stripping draw-plate machine, use of 171 

assembling 173, 180 

deep-draw work, spur-gear 176 

equipment for machine use, pattern, 172 

flange-coupling, pattern for hand molding 171 

parallel drawing de^dce for ' 179 

stripping plate and draw board 178 



INDEX 9 

PAGE 

Stripping-plate hand-rammed machine, use of ^ 182 

advantages 197 

aUgnment of patterns 191 

hand-molded patterns, conditions in 182 

match plate, use of 190 

molding machine 185 

roll back, use of 191 

stool, use of 189 

stripping plate 185 

Stripping-plate macliiur, \me of double-draw , 20b 

Stripping ring, use of 217 

characteristics of 217 

core for, inside 221 

flask construction for , 219 

T 

Template for turbine vanes 155 

Template, globe- valve 130 

Templates, gear tooth 144 

bevel- 150 

Tool equipment 7 

abrading tools : . . 36 

bevels 27 

boring, wood • 24 

calipers 31 

chisels 20 

gouges 23 

hammer and mallet 33 

lathes 40 

marking, surface 29 

planing machines 48 

planes, hand 12, 15, 17 

pliers and clamps 35 

rules, measuring 28 

sawing machines , 46 

saws, hand 7, 8, 10, 11 

screwdriver and awls 34 

spokeshave 20 

squares 26 

trimmers 49 

Trammel 30 

Try-squares 26 

Turbine case, pattern for 59 

Turbine guide ring, patterns for hand molding. . 153 

bottom core 163 

core box, use of • 161 

cover core 163 

guide vanes I55 

molding process 163 

vane corebox. , , 157 



10 INDEX 

V PAGE 

Valve, pattern for globe 128 

bonnet construction 133 

branches, construction of 131 

core, two-pprt 131 

globe construction 128 

Warping of wood 4 

correction by reversing grain 5 

Wheel pattern, hand- 55, 90 

hubs, forming 94 

rim, building 92 

spider pattern, construction of 90 

spokes, shaping 93 

Woods used as pattern material 2 

hard 3 

pine, white 2 

warping of 4 

AVoodworking, knowledge required of 1 



